Mp3 Agentabrams

Mirrors the ollama-tailscale-bridge pattern:

  com.steve.mp3-agentabrams-server          → node server.js on 127.0.0.1:9696
  com.steve.mp3-agentabrams-tailscale-bridge → socat 100.65.187.120:9696 -> 127.0.0.1:9696

Both: RunAtLoad=true, KeepAlive=true, plutil-lint clean. Logs land in
project logs/. Server plist deliberately omits MP3_HOST so server.js
keeps defaulting to loopback — Tailscale access is layered on top via
the separate bridge plist, never by exposing the server directly.

To enable on Mac2:
  cp launchd/com.steve.mp3-agentabrams-server.plist ~/Library/LaunchAgents/
  cp launchd/com.steve.mp3-agentabrams-tailscale-bridge.plist ~/Library/LaunchAgents/
  launchctl load -w ~/Library/LaunchAgents/com.steve.mp3-agentabrams-server.plist
  launchctl load -w ~/Library/LaunchAgents/com.steve.mp3-agentabrams-tailscale-bridge.plist

Verified post-load:
  loopback 127.0.0.1:9696       = 200
  tailscale 100.65.187.120:9696 = 200
  home LAN 192.168.1.53:9696    = refused

If Tailscale IP ever changes (tailscale ip -4), update bind= in the
tailscale-bridge plist and launchctl unload+load.

Initial app.listen(PORT, cb) defaulted to all interfaces; Steve caught
it on first review. The fix has two parts:

1. Pass explicit HOST to app.listen.
2. Use MP3_HOST (project-specific) instead of HOST. Steve's shell sets
   HOST=0.0.0.0 globally for other projects, which would have silently
   undone any 'default to 127.0.0.1' fix.

Override path preserved: MP3_HOST=0.0.0.0 npm start exposes on LAN.
Verified post-fix: netstat shows 127.0.0.1.9696 LISTEN only;
curl http://192.168.1.53:9696/ -> connection refused;
curl http://127.0.0.1:9696/ -> 200.

358 tracks indexed across ~/Projects/, ~/Videos/, ~/Desktop/, ~/.claude/skills/.
154MB total. Express on port 9696 (override MP3_PORT).

Stack:
  scan-mp3s.js  walks SCAN_ROOTS, writes manifest.json (gitignored)
  server.js     /api/manifest, /api/refresh (re-scan), /audio?id=<id> with
                Range support, /healthz, static public/.
  index.html    grid + list toggle, density slider (2-10 cols), sort
                (Newest/Oldest/Title/Size/Duration/Source), text + source
                filter, pseudo-waveform card art, inline range-aware player
                bar at bottom. All controls persist via localStorage mp3aa.*
                and hydrate BEFORE first render per Steve's standing rule.

Paths never appear in URLs — every track is referenced by stable sha1-12
id, so the filesystem layout is hidden from the frontend.

ffprobe duration probe gated by PROBE_DURATIONS=1 (first scan ran with
=0 for speed; durations show as -- in the UI until re-scan with
ffprobe enabled).

Next: DNS hookup at mp3.agentabrams.com (same pattern as
videos.agentabrams.com), optional auth gate if exposed publicly.