pres_mgmt: fix session QR never showing for POCs/presenters

The condition (show__session_qr || trusted_access) && show_content__session_qr
required the local per-browser toggle to also be true. Non-trusted users
(POCs, presenters) have no way to set it, so QR never appeared even when
admin had enabled it in Config.

New logic: show__session_qr alone is sufficient to generate and display the QR.
show_content__session_qr is now a staff-only override for when admin has NOT
enabled QR globally (allows trusted users to force it on per-browser).

Also: add QR Code toggle to session page Options modal (Display section),
visible to trusted staff only when admin has not already enabled it globally.

src/routes/events/[event_id]/(pres_mgmt)/session/[session_id]/session_page_menu.svelte

@@ -15,7 +15,7 @@ let {
 
 import { goto } from '$app/navigation';
 import { Modal } from 'flowbite-svelte';
-import { Clock, Info, Send, Settings, ToggleLeft, ToggleRight, X } from '@lucide/svelte';
+import { Clock, Info, QrCode, Send, Settings, ToggleLeft, ToggleRight, X } from '@lucide/svelte';
 import { ae_loc, ae_api } from '$lib/stores/ae_stores';
 import { events_slct } from '$lib/stores/ae_events_stores';
 import { pres_mgmt_loc } from '$lib/stores/ae_events_stores__pres_mgmt.svelte';
@@ -191,6 +191,33 @@ async function toggle_hide_launcher() {
                         {pres_mgmt_loc.current.use_12h ? '12-Hour Time' : '24-Hour Time'}
                     </span>
                 </button>
+
+                <!-- QR Code toggle — only shown to trusted staff and only when
+                     admin has NOT already enabled QR globally (if they have,
+                     it shows automatically without needing this toggle) -->
+                {#if $ae_loc.trusted_access && !pres_mgmt_loc.current.show__session_qr}
+                    <button
+                        type="button"
+                        onclick={() => {
+                            pres_mgmt_loc.current.show_content__session_qr =
+                                !pres_mgmt_loc.current.show_content__session_qr;
+                        }}
+                        class="btn btn-sm mt-1 w-full justify-between"
+                        class:ae_btn_surface={pres_mgmt_loc.current.show_content__session_qr}
+                        class:ae_btn_surface_outlined={!pres_mgmt_loc.current.show_content__session_qr}>
+                        {#if pres_mgmt_loc.current.show_content__session_qr}<ToggleRight
+                                size="1em"
+                                class="mr-1" />{:else}<ToggleLeft
+                                size="1em"
+                                class="mr-1" />{/if}
+                        <span class="grow">
+                            <QrCode size="1em" class="mr-1" />
+                            {pres_mgmt_loc.current.show_content__session_qr
+                                ? 'Hide QR Code'
+                                : 'Show QR Code'}
+                        </span>
+                    </button>
+                {/if}
             </section>
 
             <!-- Launcher Settings -->

src/routes/events/[event_id]/(pres_mgmt)/session/[session_id]/session_view.svelte

@@ -175,10 +175,13 @@ let poc_is_authed = $derived(
 // QR Code Generation Logic
 $events_sess.pres_mgmt.session__updated_on = null;
 $effect(() => {
+    // Generate QR when admin has enabled it (show__session_qr) OR trusted staff
+    // has turned on their local override (show_content__session_qr).
+    // show_content__session_qr is NOT required when show__session_qr is true —
+    // non-trusted users (POCs, presenters) have no way to toggle it.
     if (
         $lq__event_session_obj?.id &&
-        (pres_mgmt_loc.current.show__session_qr || $ae_loc.trusted_access) &&
+        (pres_mgmt_loc.current.show__session_qr || ($ae_loc.trusted_access && pres_mgmt_loc.current.show_content__session_qr)) &&
-        pres_mgmt_loc.current.show_content__session_qr &&
         !$events_sess.pres_mgmt.session_qr_url[$lq__event_session_obj.id]
     ) {
         $events_sess.pres_mgmt.session_qr_url[$lq__event_session_obj.id] = true;
@@ -237,7 +240,7 @@ async function send_poc_email_link() {
             <!-- QR code: floats top-right, compact by default, toggle to enlarge.
                  Only rendered once the async URL is resolved (string), never while
                  it is still the boolean `true` loading placeholder. -->
-            {#if $lq__event_session_obj && (pres_mgmt_loc.current.show__session_qr || $ae_loc.trusted_access) && typeof $events_sess.pres_mgmt.session_qr_url?.[$lq__event_session_obj.id] === 'string'}
+            {#if $lq__event_session_obj && (pres_mgmt_loc.current.show__session_qr || ($ae_loc.trusted_access && pres_mgmt_loc.current.show_content__session_qr)) && typeof $events_sess.pres_mgmt.session_qr_url?.[$lq__event_session_obj.id] === 'string'}
                 <div class="float-right mb-1 ml-3 flex flex-col items-center gap-1">
                     <button
                         type="button"