feat: Add platform-specific VLC launch profiles (macOS working; Linux deferred)

- macOS: Uses direct binary path (/Applications/VLC.app/Contents/MacOS/VLC)
  with --no-play-and-exit --play-and-pause flags and AppleScript fullscreen toggle.
  Confirmed working: pause on last frame, stays in window.

- Linux: Uses shell command (vlc --no-play-and-exit --play-and-pause).
  Known issue: not going fullscreen, not pausing on end. Deferred for later
  investigation of flag interpretation vs launcher execution layer.

- Created separate profile constants: VLC_MIRROR_MAC_PROFILE and
  VLC_MIRROR_LINUX_PROFILE in ae_launcher__default_launch_profiles.ts

- Updated TODO__Agents.md with Linux VLC issue for future debugging

Files: ae_launcher__default_launch_profiles.ts, documentation/TODO__Agents.md

documentation/TODO__Agents.md

@@ -142,10 +142,27 @@ below. The TTL + `verify_in_flight` guards are the current mitigation.
 
 ### ~~[IDAA] Server-side Novi verification — 503 not auto-retried~~ ✅ Fixed (2026-05-20)
 
-Fixed in commit `42f40e990` — added `503` status check in `verify_novi_uuid()` before the
-generic `!response.ok` throw. On first 503, waits 3s and auto-retries (same path as network
-errors). After two consecutive 503s, surfaces "Verification Unavailable" as intended.
-File: `src/routes/idaa/(idaa)/+layout.svelte`.
+---
+
+### [Launcher/VLC] Linux playback — fullscreen + pause-on-end not working
+**Status:** Mac ✅ working perfectly; Linux 🚧 deferred for later investigation
+**Date discovered:** 2026-05-20
+
+macOS VLC profile (direct binary path) successfully:
+- Opens VLC with the media file
+- Plays + pauses on the last frame (instead of returning to playlist)
+- Fullscreen toggle works (Cmd+F via AppleScript post-script)
+
+Linux VLC command (`vlc --no-play-and-exit --play-and-pause "{{path}}"`) currently:
+- Does NOT go fullscreen
+- Does NOT pause on the last frame (plays through, returns to playlist)
+
+**Current state:** Both macOS and Linux commands in `ae_launcher__default_launch_profiles.ts`.
+macOS is the primary venue deployment platform; Linux support is nice-to-have.
+
+**Investigation needed:** Determine if the VLC flags are being interpreted on Linux,
+or if there's a launcher execution layer issue (e.g. `shell:` prefix handling).
+File: `src/lib/ae_events/ae_launcher__default_launch_profiles.ts` — `make_vlc_mirror_linux_profile()`.
 
 ---