media-pc: add JellyCon, display server, and HDR decisions

Decided on Kodi + JellyCon with NFS direct path for media playback,
Sway/Hyprland for display server with workspace-based browser switching,
and noted HDR status for future reference.

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

docs/plans/media-pc-replacement.md

@@ -145,14 +145,47 @@ A mini PC running NixOS with a lightweight Wayland compositor, launching Kodi fo
 - Natural fit alongside the other 16 NixOS hosts in this repo
 - Dedicated devices lose the browser/keyboard workflow
 
-### Twitch/YouTube in Kodi
+### Display Server: Sway/Hyprland
 
-Several approaches, can mix and match:
+Options evaluated:
-- **sendtokodi** addon + yt-dlp — paste/send URLs, plays via yt-dlp backend. Supports Twitch and YouTube.
-- **Kodi web browser** — launch a full browser from within Kodi (falls back to keyboard input)
-- **Tube addon** / YouTube plugin — dedicated YouTube browsing within Kodi UI
 
-The browser fallback with the wireless keyboard means streaming sites will always work even if Kodi addons are flaky.
+| Approach | Pros | Cons |
+|----------|------|------|
+| Cage (kiosk) | Simplest, single-app | No browser without TTY switching |
+| kodi-gbm (no compositor) | Best HDR support | No browser at all, ALSA-only audio |
+| **Sway/Hyprland** | **Workspace switching, VA-API in browser** | **Slightly more config** |
+| Full DE (GNOME/KDE) | Everything works | Overkill, heavy |
+
+**Decision: Sway or Hyprland** (Hyprland preferred — same as desktop)
+
+- Kodi fullscreen on workspace 1, Firefox on workspace 2
+- Switch via keybinding on wireless keyboard
+- Auto-start both on login via greetd
+- Minimal config — no bar, no decorations, just workspaces
+- VA-API hardware decode works in Firefox on Wayland (important for YouTube/Twitch)
+- Can revisit kodi-gbm later if HDR becomes a priority (just a config change)
+
+### Twitch/YouTube
+
+Firefox on workspace 2, switched to via keyboard. Kodi addons (sendtokodi, YouTube plugin) available as secondary options but a real browser is the primary approach.
+
+### Media Playback: Kodi + JellyCon + NFS Direct Path
+
+Three options were evaluated for media playback:
+
+| Approach | Transcoding | Library management | Watch state sync |
+|----------|-------------|-------------------|-----------------|
+| Jellyfin only (browser) | Yes — browsers lack codec support for DTS, PGS subs, etc. | Jellyfin | Jellyfin |
+| Kodi + NFS only | No — Kodi plays everything natively | Kodi local DB | None |
+| **Kodi + JellyCon + NFS** | **No — Kodi's native player, direct path via NFS** | **Jellyfin** | **Jellyfin** |
+
+**Decision: Kodi + JellyCon with NFS direct path**
+
+- JellyCon presents the Jellyfin library inside Kodi's UI (browse, search, metadata, artwork)
+- Playback uses Kodi's native player — direct play, no transcoding, full codec support including surround passthrough
+- JellyCon's "direct path" mode maps Jellyfin paths to local NFS mounts, so playback goes straight over NFS without streaming through Jellyfin's HTTP layer
+- Watch state, resume position, etc. sync back to Jellyfin — accessible from other devices too
+- NFS mount follows the same pattern as jelly01 (`nas.home.2rjus.net:/mnt/hdd-pool/media`)
 
 ### Audio Passthrough