feat(launcher): skip wallpaper gsettings on Linux, show dev popup instead

Running gsettings on the dev workstation resets monitors on every test cycle.
Linux Electron handler now returns linux_test_mode:true with would_run details
instead of applying. Svelte cfg component shows a debug popup (mirrors Native
Test Mode style). Background sync logs to console and leaves applied-URL unset.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

documentation/TODO__Agents.md

@@ -20,19 +20,12 @@ guessing defaults.
 - [x] `native:copy-from-cache-to-temp` primitive added — copy to tmp, caller decides launch
 - [x] `native:launch-from-cache` executes a provided `native_template` string — AppleScript or `shell:` prefix; no Electron-side fallback
 - [x] `get_launch_profile()` in `launcher_file_cont.svelte` reads from device config then event config; resolves to a `native_template` string and passes it to `launch_from_cache`
-- [x] Built-in Launcher defaults refactored into canonical profile names plus extension aliases
+- [x] Built-in Launcher defaults refactored into canonical profile names plus extension aliases (`ae_launcher__default_launch_profiles.ts`)
 - [x] Device-level Launch Timing section added under Launcher Configuration → Device, with per-profile `launch_profiles[profile].post_delay_ms` overrides
+- [x] **URL file launch support (2026-05-13)** — `event_file.extension = 'URL'` (or filename starting with `http://`/`https://`) is treated as a non-downloaded URL. Background sync skips URL files so they are never treated as cacheable hosted files. Shared `AE_Comp_Hosted_Files_Download_Button` now hard-bypasses the download path for URL records. In native mode, `handle_open_file()` routes to `native.open_external({ url, app: 'chrome' })` with `'default'` fallback. Health section crash fixed (guarded `native_device` against undefined in preview/edit mode).
 
 **Svelte-side migration — remaining before May 26:**
-- [ ] **[Launcher] Built-in Svelte default profiles** — move the built-in presentation/media
-  policy objects into a Svelte constants file (e.g. `ae_launcher__default_launch_profiles.ts`).
-  Use canonical profile names plus extension aliases so the media family does not repeat the
-  same VLC config for every file type. Cover the core macOS set (`pptx`, `ppt`, `key`, `odp`,
-  `pdf`), the media set (`mp4`, `mkv`, `mp3`, and related media types), the Windows /
-  Parallels variants (`pptxwin`, `pptwin`, `odpwin`, `pdfwin`), and the URL/web-based
-  presentation path. Priority: `get_launch_profile()` already checks device config and event
-  config; add a 3rd fallback to these Svelte defaults before returning `null`. Keep the
-  fallback in Svelte, not in Electron.
+- [x] **[Launcher] Built-in Svelte default profiles (2026-05-11)** — canonical profile constants live in `ae_launcher__default_launch_profiles.ts` with extension aliases and a `resolve_launch_profile()` 3-step fallback (device config → event config → built-in defaults). Covers macOS (`pptx`, `ppt`, `key`, `odp`, `pdf`), media (`mp4`, `mkv`, `mp3`, etc.), Windows/Parallels variants, and URL path.
 - [ ] **[Launcher] Composable open flow** — refactor `handle_open_file()` to use
   `copy_from_cache_to_temp` + `run_osascript` / `run_cmd` directly instead of the all-in-one
   `launch_from_cache`. Finer error handling at each step (verify copy succeeded before

src/lib/electron/electron_relay.ts

@@ -384,13 +384,65 @@ export async function control_presentation({
 
 // 4. System Management (Phase 5+)
 
-export async function set_wallpaper({ path }: { path: string }) {
+export async function set_wallpaper({
+    path,
+    url,
+    url_external,
+    display = 'all',
+    api_key,
+    account_id
+}: {
+    /** Local file path (existing behavior). */
+    path?: string;
+    /** HTTPS URL — downloaded to ~/Library/Caches/OSIT/wallpaper/ before applying. */
+    url?: string;
+    /** Optional separate URL for the external/projector display only. */
+    url_external?: string;
+    /** Which display(s) to target. Defaults to 'all'. */
+    display?: 'all' | 'primary' | 'external';
+    /** Aether API key passed as x-aether-api-key header on the download request. */
+    api_key?: string;
+    /** Aether account ID passed as x-account-id header on the download request. */
+    account_id?: string;
+}) {
     if (!native || !native.set_wallpaper)
         return {
             success: false,
             error: 'Native handler set_wallpaper not available'
         };
-    return await native.set_wallpaper({ path });
+    return await native.set_wallpaper({ path, url, url_external, display, api_key, account_id });
+}
+
+/**
+ * Restores the macOS default wallpaper on all displays.
+ * Scans /System/Library/Desktop Pictures/ for the first .heic file — works across
+ * all recent macOS versions without needing to know the version name.
+ * No-op on non-macOS (Linux/Windows return success:false from run_osascript).
+ */
+export async function restore_macos_default_wallpaper(
+    display: 'all' | 'primary' | 'external' = 'all'
+): Promise<{ success: boolean; error?: string }> {
+    const display_target =
+        display === 'primary'
+            ? 'tell desktop 1'
+            : display === 'external'
+              ? 'tell desktop 2'
+              : 'tell every desktop';
+
+    const script = `
+set pic_path to do shell script "ls '/System/Library/Desktop Pictures/'*.heic 2>/dev/null | head -1"
+if pic_path is "" then
+    error "No default macOS wallpaper (.heic) found in /System/Library/Desktop Pictures/"
+end if
+tell application "System Events"
+    ${display_target}
+        set picture to pic_path
+    end tell
+end tell
+`.trim();
+
+    const result = await run_osascript(script);
+    return result ?? { success: false, error: 'Native bridge not available' };
 }
 
 export async function update_app(args: {

src/lib/stores/ae_events_stores__launcher_defaults.ts

@@ -39,12 +39,17 @@ export interface LauncherLocState {
     section_state__health: SectionState;
     section_state__native_os: SectionState;
     section_state__launch_timing: SectionState;
+    section_state__wallpaper: SectionState;
     section_state__sync_timers: SectionState;
     section_state__updates: SectionState;
     section_state__controller: SectionState;
     section_state__screen_saver: SectionState;
     section_state__app_modes: SectionState;
     section_state__local_actions: SectionState;
+    /** URL last successfully applied as wallpaper on this device. Used to detect remote config changes. */
+    wallpaper_applied_url: string | null;
+    /** URL last applied to the external display (when url_external is configured). */
+    wallpaper_applied_url_external: string | null;
     datetime_format: string;
     time_format: string;
     time_hours: 12 | 24;
@@ -160,6 +165,7 @@ export const launcher_loc_defaults: LauncherLocState = {
     section_state__health: 'auto',
     section_state__native_os: 'collapsed',
     section_state__launch_timing: 'collapsed',
+    section_state__wallpaper: 'collapsed',
     section_state__sync_timers: 'collapsed',
     section_state__updates: 'collapsed',
     section_state__controller: 'auto',
@@ -208,7 +214,9 @@ export const launcher_loc_defaults: LauncherLocState = {
     controller: 'local',
     controller_group_code: 'launcher-00',
     controller_client_id: null,
-    native_test_mode: false
+    native_test_mode: false,
+    wallpaper_applied_url: null,
+    wallpaper_applied_url_external: null
     // controller_cmd: null,
     // controller_trigger_send: null,
 };

src/routes/events/[event_id]/(launcher)/cfg_components/launcher_cfg_wallpaper.svelte

@@ -0,0 +1,410 @@
+<script lang="ts">
+import { ae_api, ae_loc } from '$lib/stores/ae_stores';
+import { events_func } from '$lib/ae_events/ae_events_functions';
+import { events_loc } from '$lib/stores/ae_events_stores';
+import * as native from '$lib/electron/electron_relay';
+import Launcher_Cfg_Section from './launcher_cfg_section.svelte';
+import { FlaskConical, Image, Monitor, RotateCcw, Save, Zap } from '@lucide/svelte';
+
+interface Props {
+    on_expand?: () => void;
+}
+
+let { on_expand }: Props = $props();
+
+type NativeDeviceLike = {
+    event_device_id?: string;
+    id?: string;
+    other_json?: string | Record<string, unknown> | null;
+    [key: string]: unknown;
+};
+
+let url_input = $state('');
+let url_external_input = $state('');
+let save_status = $state('');
+let apply_status = $state('');
+let restore_status = $state('');
+let last_device_id: string | null = null;
+
+let linux_test_popup_open = $state(false);
+let linux_test_popup_data = $state<Record<string, unknown> | null>(null);
+
+function get_native_device(): NativeDeviceLike | null {
+    const store_loc = $ae_loc as { native_device?: NativeDeviceLike };
+    return store_loc.native_device ?? null;
+}
+
+function get_device_id(): string | null {
+    const native_device = get_native_device();
+    return native_device?.event_device_id ?? native_device?.id ?? null;
+}
+
+function parse_other_json(raw_json: unknown): Record<string, unknown> {
+    if (!raw_json) return {};
+    if (typeof raw_json === 'object') return { ...(raw_json as Record<string, unknown>) };
+    if (typeof raw_json !== 'string') return {};
+    try {
+        const parsed = JSON.parse(raw_json);
+        return parsed && typeof parsed === 'object' ? { ...parsed } : {};
+    } catch {
+        return {};
+    }
+}
+
+function get_configured_wallpaper(): { url?: string; url_external?: string } {
+    const native_device = get_native_device();
+    const other_json = parse_other_json(native_device?.other_json);
+    const launcher_cfg = (other_json.launcher as Record<string, unknown> | undefined) ?? {};
+    return (launcher_cfg.wallpaper as { url?: string; url_external?: string } | undefined) ?? {};
+}
+
+function sync_from_device() {
+    const device_id = get_device_id();
+    if (device_id === last_device_id) return;
+    last_device_id = device_id;
+    const configured = get_configured_wallpaper();
+    url_input = configured.url ?? '';
+    url_external_input = configured.url_external ?? '';
+}
+
+sync_from_device();
+
+$effect(() => {
+    sync_from_device();
+});
+
+function set_save_status(msg: string) {
+    save_status = msg;
+    setTimeout(() => { if (save_status === msg) save_status = ''; }, 3000);
+}
+
+function set_apply_status(msg: string) {
+    apply_status = msg;
+    setTimeout(() => { if (apply_status === msg) apply_status = ''; }, 4000);
+}
+
+async function handle_save() {
+    const device_id = get_device_id();
+    if (!device_id) { set_save_status('No device loaded'); return; }
+
+    const native_device = get_native_device();
+    const other_json_obj = parse_other_json(native_device?.other_json);
+    const launcher_cfg: Record<string, unknown> = {
+        ...((other_json_obj.launcher as Record<string, unknown> | undefined) ?? {})
+    };
+
+    const wallpaper: Record<string, string> = {};
+    if (url_input.trim()) wallpaper.url = url_input.trim();
+    if (url_external_input.trim()) wallpaper.url_external = url_external_input.trim();
+
+    if (Object.keys(wallpaper).length > 0) {
+        launcher_cfg.wallpaper = wallpaper;
+    } else {
+        delete launcher_cfg.wallpaper;
+    }
+
+    if (Object.keys(launcher_cfg).length > 0) {
+        other_json_obj.launcher = launcher_cfg;
+    } else {
+        delete other_json_obj.launcher;
+    }
+
+    const other_json = JSON.stringify(other_json_obj);
+    set_save_status('Saving...');
+
+    const result = await events_func.update_ae_obj__event_device({
+        api_cfg: $ae_api,
+        event_device_id: device_id,
+        data_kv: { other_json },
+        log_lvl: 0
+    });
+
+    if (!result) { set_save_status('Save failed'); return; }
+
+    const store_loc = $ae_loc as { native_device?: NativeDeviceLike };
+    store_loc.native_device = { ...get_native_device(), ...result, other_json };
+    set_save_status('Saved');
+}
+
+async function handle_apply() {
+    const url = url_input.trim();
+    const url_ext = url_external_input.trim();
+    if (!url && !url_ext) { set_apply_status('Enter a URL first'); return; }
+
+    // If only external is set, target only that display so the built-in stays unchanged.
+    const display = !url && url_ext ? 'external' : 'all';
+
+    set_apply_status('Downloading & applying...');
+    const result = await native.set_wallpaper({
+        url: url || undefined,
+        url_external: url_ext || undefined,
+        display,
+        api_key: $ae_api.api_secret_key,
+        account_id: String($ae_api.account_id ?? '')
+    });
+
+    if (result?.success && (result as any).linux_test_mode) {
+        linux_test_popup_data = result as Record<string, unknown>;
+        linux_test_popup_open = true;
+        set_apply_status('Linux dev mode — see popup');
+    } else if (result?.success) {
+        $events_loc.launcher.wallpaper_applied_url = url || null;
+        $events_loc.launcher.wallpaper_applied_url_external = url_ext || null;
+        set_apply_status('Applied ✓');
+    } else {
+        set_apply_status(`Error: ${(result as any)?.error ?? 'Unknown error'}`);
+    }
+}
+
+async function handle_restore_default() {
+    restore_status = 'Restoring...';
+    const result = await native.restore_macos_default_wallpaper('all');
+    if (result?.success) {
+        // Clear tracked applied URL so the next config URL re-applies correctly.
+        $events_loc.launcher.wallpaper_applied_url = null;
+        $events_loc.launcher.wallpaper_applied_url_external = null;
+        restore_status = 'Restored ✓';
+    } else {
+        restore_status = `Error: ${(result as any)?.error ?? 'Unknown error'}`;
+    }
+    setTimeout(() => { if (restore_status.startsWith('Restored') || restore_status.startsWith('Error')) restore_status = ''; }, 4000);
+}
+
+async function handle_save_and_apply() {
+    await handle_save();
+    if (save_status !== 'Save failed' && save_status !== 'No device loaded') {
+        await handle_apply();
+    }
+}
+
+const configured_url = $derived(get_configured_wallpaper().url ?? '');
+const is_applied = $derived(
+    !!url_input.trim() &&
+    $events_loc.launcher.wallpaper_applied_url === url_input.trim()
+);
+const section_description = $derived(
+    configured_url
+        ? is_applied
+            ? 'Configured • Applied ✓'
+            : 'Configured • Pending'
+        : 'Not configured'
+);
+</script>
+
+<Launcher_Cfg_Section
+    title="Wallpaper"
+    icon={Image}
+    bind:state={$events_loc.launcher.section_state__wallpaper}
+    {on_expand}
+    description={section_description}>
+
+    {#if $ae_loc.edit_mode && !$ae_loc.is_native}
+        <div
+            class="bg-warning-500/10 border-warning-500/30 mb-1 flex items-center gap-2 rounded-lg border px-2 py-1.5">
+            <FlaskConical size="0.75em" class="text-warning-500" />
+            <span class="text-warning-500 text-[9px] font-bold tracking-wide uppercase">
+                Dev Preview — Apply requires Electron; Save works from any device
+            </span>
+        </div>
+    {/if}
+
+    <div class="flex flex-col gap-3">
+        <p class="ml-1 text-[9px] font-bold uppercase opacity-50">
+            Desktop Background Images
+        </p>
+        <p class="ml-1 text-[10px] leading-snug opacity-60">
+            Paste an HTTPS image URL. Save writes it to this device's config so all
+            devices auto-apply on their next heartbeat. Apply sets it immediately on
+            this machine.
+        </p>
+
+        {#if !get_device_id()}
+            <div
+                class="bg-warning-500/10 border-warning-500/20 rounded-lg border px-2 py-2 text-[9px] opacity-80">
+                No device record loaded — Save requires a native device config.
+            </div>
+        {/if}
+
+        <!-- All Displays (primary URL) -->
+        <section class="border-surface-500/10 rounded-lg border p-2">
+            <div class="mb-1.5 flex items-center gap-1.5">
+                <Monitor size="0.85em" class="opacity-50" />
+                <p class="text-[10px] font-bold uppercase tracking-wide">
+                    All Displays
+                </p>
+                {#if is_applied}
+                    <span
+                        class="text-success-500 ml-auto text-[9px] font-bold">Applied ✓</span>
+                {:else if $events_loc.launcher.wallpaper_applied_url}
+                    <span class="text-warning-500 ml-auto text-[9px] italic"
+                        >Pending apply</span>
+                {/if}
+            </div>
+            <input
+                type="url"
+                bind:value={url_input}
+                placeholder="https://example.com/wallpaper.jpg"
+                class="input input-sm preset-tonal-surface mb-1.5 h-8 w-full text-[10px]" />
+            {#if $events_loc.launcher.wallpaper_applied_url && $events_loc.launcher.wallpaper_applied_url !== url_input.trim()}
+                <p class="text-[9px] italic opacity-40 truncate">
+                    Applied: {$events_loc.launcher.wallpaper_applied_url}
+                </p>
+            {/if}
+        </section>
+
+        <!-- External Display (optional override) -->
+        <section class="border-surface-500/10 rounded-lg border p-2">
+            <div class="mb-1.5 flex items-center gap-1.5">
+                <Monitor size="0.85em" class="opacity-40" />
+                <p class="text-[10px] font-bold uppercase tracking-wide">
+                    External / Projector
+                    <span class="ml-1 font-normal normal-case opacity-50">(optional)</span>
+                </p>
+            </div>
+            <p class="mb-1.5 text-[9px] leading-snug opacity-50">
+                Leave blank to use the same image on all displays.
+            </p>
+            <input
+                type="url"
+                bind:value={url_external_input}
+                placeholder="https://example.com/projector-bg.jpg"
+                class="input input-sm preset-tonal-surface h-8 w-full text-[10px]" />
+        </section>
+
+        <!-- Action Buttons -->
+        <div class="grid grid-cols-2 gap-2">
+            <button
+                type="button"
+                onclick={handle_save}
+                disabled={!get_device_id()}
+                class="btn btn-sm preset-tonal-surface h-8 text-[10px]">
+                <Save size="0.8em" class="mr-1" /> Save Config
+            </button>
+            <button
+                type="button"
+                onclick={handle_apply}
+                disabled={!url_input.trim() && !url_external_input.trim()}
+                class="btn btn-sm preset-tonal-primary h-8 text-[10px]">
+                <Zap size="0.8em" class="mr-1" /> Apply Now
+            </button>
+        </div>
+        <button
+            type="button"
+            onclick={handle_save_and_apply}
+            disabled={!get_device_id() || (!url_input.trim() && !url_external_input.trim())}
+            class="btn btn-sm preset-filled-primary h-8 w-full text-[10px] font-bold">
+            <Save size="0.8em" class="mr-1" />
+            <Zap size="0.8em" class="mr-1" />
+            Save & Apply
+        </button>
+
+        <!-- Restore macOS default — safety valve for end-of-show cleanup -->
+        {#if $ae_loc.is_native || $ae_loc.edit_mode}
+            <button
+                type="button"
+                onclick={handle_restore_default}
+                class="btn btn-sm preset-tonal-surface h-8 w-full text-[10px] opacity-60 hover:opacity-100">
+                <RotateCcw size="0.8em" class="mr-1" /> Restore macOS Default
+            </button>
+        {/if}
+
+        {#if save_status}
+            <div
+                class="text-primary-500 text-center text-[9px] italic"
+                class:text-error-500={save_status.includes('failed') || save_status.includes('No device')}>
+                {save_status}
+            </div>
+        {/if}
+        {#if apply_status}
+            <div
+                class="text-[9px] italic text-center"
+                class:text-success-500={apply_status.includes('✓')}
+                class:text-primary-500={apply_status.includes('Downloading')}
+                class:text-error-500={apply_status.includes('Error')}>
+                {apply_status}
+            </div>
+        {/if}
+        {#if restore_status}
+            <div
+                class="text-[9px] italic text-center"
+                class:text-success-500={restore_status.includes('✓')}
+                class:text-primary-500={restore_status === 'Restoring...'}
+                class:text-error-500={restore_status.includes('Error')}>
+                {restore_status}
+            </div>
+        {/if}
+    </div>
+</Launcher_Cfg_Section>
+
+<!-- Linux Dev Mode Popup — mirrors Native Test Mode style -->
+<!-- Shows what WOULD have been applied; actual gsettings call is skipped to avoid
+     resetting the dev workstation monitors on every test cycle. -->
+{#if linux_test_popup_open && linux_test_popup_data}
+    <!-- svelte-ignore a11y_click_events_have_key_events a11y_no_static_element_interactions -->
+    <div
+        class="fixed inset-0 z-9999 flex items-center justify-center bg-black/70 p-4"
+        role="presentation"
+        onclick={() => (linux_test_popup_open = false)}>
+        <!-- svelte-ignore a11y_click_events_have_key_events a11y_no_static_element_interactions -->
+        <div
+            class="bg-surface-50/95 dark:bg-surface-900/95 border-warning-500/40 relative flex max-h-[90vh] w-full max-w-lg flex-col gap-0 overflow-hidden rounded-xl border shadow-2xl"
+            role="dialog"
+            aria-modal="true"
+            aria-label="Linux Dev Mode — Wallpaper not applied"
+            tabindex="-1"
+            onclick={(e) => e.stopPropagation()}>
+
+            <div class="bg-warning-500/10 border-warning-500/30 flex items-center gap-2 border-b px-4 py-3">
+                <span class="text-warning-600 dark:text-warning-400 font-mono text-xs font-bold uppercase tracking-wider">
+                    🧪 Linux Dev Mode — Wallpaper not applied
+                </span>
+                <button
+                    type="button"
+                    onclick={() => (linux_test_popup_open = false)}
+                    class="btn btn-xs preset-tonal-surface ml-auto">
+                    Close
+                </button>
+            </div>
+
+            <div class="flex flex-col gap-3 overflow-y-auto p-4 font-mono text-xs">
+                <div class="flex flex-col gap-1">
+                    <span class="text-[9px] font-bold uppercase opacity-50">Display Target</span>
+                    <div class="rounded bg-surface-500/10 px-3 py-2">
+                        {linux_test_popup_data.display ?? 'all'}
+                    </div>
+                </div>
+
+                {#if linux_test_popup_data.url}
+                    <div class="flex flex-col gap-1">
+                        <span class="text-[9px] font-bold uppercase opacity-50">Primary URL</span>
+                        <div class="text-primary-500 rounded bg-surface-500/10 px-3 py-2 break-all">
+                            {linux_test_popup_data.url}
+                        </div>
+                    </div>
+                {/if}
+
+                {#if linux_test_popup_data.url_external}
+                    <div class="flex flex-col gap-1">
+                        <span class="text-[9px] font-bold uppercase opacity-50">External / Projector URL</span>
+                        <div class="text-primary-500 rounded bg-surface-500/10 px-3 py-2 break-all">
+                            {linux_test_popup_data.url_external}
+                        </div>
+                    </div>
+                {/if}
+
+                <div class="flex flex-col gap-1">
+                    <span class="text-[9px] font-bold uppercase opacity-50">Would Have Run</span>
+                    <div class="rounded bg-surface-500/10 px-3 py-2 leading-relaxed whitespace-pre-wrap text-success-600 dark:text-success-400">
+                        {#each (linux_test_popup_data.would_run as string[]) as cmd}
+                            <div class="mb-1">{cmd}</div>
+                        {/each}
+                    </div>
+                </div>
+
+                <p class="text-[9px] italic opacity-40">
+                    gsettings is skipped on Linux to avoid resetting dev monitors. On macOS this applies via osascript.
+                </p>
+            </div>
+        </div>
+    </div>
+{/if}

src/routes/events/[event_id]/(launcher)/launcher_background_sync.svelte

@@ -17,6 +17,73 @@ import { db_events } from '$lib/ae_events/db_events';
 import * as native from '$lib/electron/electron_relay';
 const { cleanup_tmp_files } = native;
 
+/**
+ * Parses other_json (string or object) into a plain Record.
+ * Duplicated from launcher_cfg_wallpaper to keep this component self-contained.
+ */
+function parse_other_json(raw: unknown): Record<string, unknown> {
+    if (!raw) return {};
+    if (typeof raw === 'object') return { ...(raw as Record<string, unknown>) };
+    if (typeof raw !== 'string') return {};
+    try {
+        const parsed = JSON.parse(raw);
+        return parsed && typeof parsed === 'object' ? { ...parsed } : {};
+    } catch {
+        return {};
+    }
+}
+
+/**
+ * Auto-applies the configured wallpaper if the URL in device config differs from
+ * what was last applied on this machine. Called at startup and after each heartbeat.
+ *
+ * WHY: staff updates the wallpaper URL in the device config once (from any machine);
+ * all native Launcher instances pick it up within one heartbeat cycle (~60s) without
+ * anyone needing to visit each podium Mac physically.
+ */
+async function apply_wallpaper_if_changed(device_other_json: unknown) {
+    if (!$ae_loc.is_native) return;
+
+    const other = parse_other_json(device_other_json);
+    const launcher_cfg = (other.launcher as Record<string, unknown> | undefined) ?? {};
+    const wallpaper = (launcher_cfg.wallpaper as { url?: string; url_external?: string } | undefined) ?? {};
+
+    const configured_url = wallpaper.url ?? '';
+    const configured_url_external = wallpaper.url_external ?? '';
+    const applied_url = $events_loc.launcher.wallpaper_applied_url ?? '';
+    const applied_url_external = $events_loc.launcher.wallpaper_applied_url_external ?? '';
+
+    const url_changed = configured_url && configured_url !== applied_url;
+    const ext_changed = configured_url_external !== applied_url_external;
+
+    if (!url_changed && !ext_changed) return;
+
+    if (log_lvl) console.log('Sync: Wallpaper config changed — applying.', { configured_url, applied_url });
+
+    // If only the external URL is configured, leave the built-in display unchanged.
+    const display = !configured_url && configured_url_external ? 'external' : 'all';
+
+    const result = await native.set_wallpaper({
+        url: configured_url || undefined,
+        url_external: configured_url_external || undefined,
+        display,
+        api_key: $ae_api.api_secret_key,
+        account_id: String($ae_api.account_id ?? '')
+    });
+
+    if (result?.success && (result as any).linux_test_mode) {
+        // Linux dev mode: gsettings was skipped. Log and leave applied URL unset so
+        // the cfg component popup can show the details when triggered manually.
+        console.info('Sync: Wallpaper linux_test_mode — would have applied:', (result as any).would_run);
+    } else if (result?.success) {
+        $events_loc.launcher.wallpaper_applied_url = configured_url || null;
+        $events_loc.launcher.wallpaper_applied_url_external = configured_url_external || null;
+        if (log_lvl) console.log('Sync: Wallpaper applied.');
+    } else {
+        console.warn('Sync: Wallpaper apply failed.', (result as any)?.error);
+    }
+}
+
 let { log_lvl = 1 } = $props();
 
 let currently_syncing: string | null = $state(null);
@@ -134,6 +201,12 @@ onMount(async () => {
     run_device_heartbeat();
     refresh_location_config();
 
+    // On startup: apply wallpaper if the device config has one that differs from
+    // what was last applied (covers reboots and first-time device setup).
+    if ($ae_loc.is_native) {
+        apply_wallpaper_if_changed($ae_loc.native_device?.other_json);
+    }
+
     // Stagger initial data fetches
     setTimeout(() => refresh_session_data(), 1000);
     setTimeout(() => refresh_presentation_data(), 3000);
@@ -432,13 +505,19 @@ async function run_device_heartbeat() {
             update_payload.notes = 'Heartbeat from non-native web session.';
         }
 
-        await events_func.update_ae_obj__event_device({
+        const heartbeat_result = await events_func.update_ae_obj__event_device({
             api_cfg: $ae_api,
             event_device_id: String(device_id),
             data_kv: update_payload,
             log_lvl: 0
         });
 
+        // V3 PATCH returns the full updated record. Use it to detect wallpaper
+        // config changes made remotely (e.g. staff updated other_json from another device).
+        if (heartbeat_result) {
+            apply_wallpaper_if_changed((heartbeat_result as any).other_json);
+        }
+
         last_heartbeat = new Date().toLocaleTimeString();
         $events_sess.launcher.heartbeat_info = {
             last_timestamp: last_heartbeat,

src/routes/events/[event_id]/(launcher)/launcher_cfg.svelte

@@ -33,6 +33,7 @@ import Launcher_Cfg_Screen_Saver from './cfg_components/launcher_cfg_screen_save
 import Launcher_Cfg_App_Modes from './cfg_components/launcher_cfg_app_modes.svelte';
 import Launcher_Cfg_Local_Actions from './cfg_components/launcher_cfg_local_actions.svelte';
 import Launcher_Cfg_Launch_Timing from './cfg_components/launcher_cfg_launch_timing.svelte';
+import Launcher_Cfg_Wallpaper from './cfg_components/launcher_cfg_wallpaper.svelte';
 import {
     Bug,
     Code,
@@ -181,6 +182,8 @@ function handle_section_expand(current_key: string) {
                         on_expand={() => handle_section_expand('health')} />
                     <Launcher_Cfg_Native_OS
                         on_expand={() => handle_section_expand('native_os')} />
+                    <Launcher_Cfg_Wallpaper
+                        on_expand={() => handle_section_expand('wallpaper')} />
                     <Launcher_Cfg_Launch_Timing
                         on_expand={() => handle_section_expand('launch_timing')} />
                     {#if $ae_loc.is_native}