docs(13-04): complete music model + tag extraction plan — summary, state, config

- 13-04-SUMMARY.md: all 3 tasks, broken-pipe recovery (verbatim wip
  checkpoint be8f24b4), MP3 fixture off-by-one deviation, 7/7 tests green
- STATE.md: 13-04 complete (7/15 phase-13 plans), D-13 decision + lofty
  gate recorded in accumulated context, next = waves 3+
- config.json: fold in pre-existing use_worktrees=false from the broken
  session (wave-continue bookkeeping, intentionally kept)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.planning/STATE.md

@@ -5,15 +5,15 @@ milestone_name: milestone
 current_phase: 13
 current_phase_name: aiui-functional-conversational-node-control-and-content-surf
 status: executing
-stopped_at: "13-09 COMPLETE 2026-08-04 (session broke on a pipe right after Task 4 finished; summary recovered+committed on resume). Task 4 resolved with operator approval: live nginx config MERGED (repo base, :443 block kept removed, /api/peer-content/ + /ext/ demo proxies preserved; rollback at /etc/nginx/archipelago.conf.bak-pre-1302-sync; sites-enabled/archipelago is a SYMLINK — back up the TARGET). Browser steps 5-7 verified via playwright Chromium on the real node: AIUI renders in the Chat iframe, fetch('/rpc/v1') CSP-BLOCKED from inside the frame but 200 from top-level (T-13-54 mitigated), embedded chat answered via the node's Claude key. CSP header re-confirmed live on resume. NEXT: execute 13-04, then waves 3+. Window 20 (NEW): repo/ISO nginx config lacks /api/peer-content/ — fresh installs silently lose peer media streaming; decide add-or-retire. Still open for operator: merge chore/aiui-monorepo-migration to main before next OTA; Claude key on archy-x250-dev3; window 18 (nginx self-heal reverting /etc/nginx deploys) at next OTA. Stale-but-harmless: p13-01/p13-02 worktrees (merged, safe to remove); stale phase-09 HANDOFF.json in .planning/ predates this and is NOT a resume source. Prior 13-09 detail preserved in git history of this file (b3b580aa)."
-last_updated: "2026-08-04T08:24:00.000Z"
+stopped_at: "13-04 COMPLETE 2026-08-04 (session broke on a pipe mid-Task-3; recovered work was checkpoint-committed VERBATIM as be8f24b4, then completed on top — no history rewrite). All 3 tasks done: Task 1 operator decision bca4660a (13-MUSIC-MODEL.md: hybrid-identity, derived-albums, index-format-json, sources=both, MUSIC_SCHEMA_VERSION=1); Task 2 operator-approved lofty 0.24.0 legitimacy gate 61564440; Task 3 tag extraction be8f24b4+4b577493 (7/7 music:: tests green; deviation: MP3 fixture frame length 210→209 — lofty truncates the division BEFORE adding padding; fixture-only fix verified against lofty's vendored source). NEXT: waves 3+ per ROADMAP/plan dependencies (13-04 was the last wave-2 plan). Window 20 still open: repo/ISO nginx config lacks /api/peer-content/ — fresh installs silently lose peer media streaming; decide add-or-retire. Still open for operator: merge chore/aiui-monorepo-migration to main before next OTA; Claude key on archy-x250-dev3; window 18 (nginx self-heal reverting /etc/nginx deploys) at next OTA. Stale-but-harmless: p13-01/p13-02 worktrees (merged, safe to remove); stale phase-09 HANDOFF.json in .planning/ predates this and is NOT a resume source. Prior 13-09 detail preserved in git history of this file (bf9b4e6a)."
+last_updated: "2026-08-04T10:50:00.000Z"
 last_activity: 2026-08-04
-last_activity_desc: "13-09 COMPLETE — Task 4 nginx sync + browser verification done; summary recovered after broken-pipe and committed. Next: 13-04"
+last_activity_desc: "13-04 complete — D-13 music model decided, lofty gated in, tag extraction 7/7 green. Next: waves 3+"
 progress:
   total_phases: 13
   completed_phases: 2
   total_plans: 60
-  completed_plans: 40
+  completed_plans: 45
   percent: 15
 ---
 
@@ -29,9 +29,9 @@ See: .planning/PROJECT.md (updated 2026-07-29)
 ## Current Position
 
 Phase: 13 (aiui-functional-conversational-node-control-and-content-surf) — EXECUTING
-Plan: 6 of 15 complete (13-01, 13-02, 13-03, 13-05, 13-06, 13-09) — next: 13-04, then waves 3+
+Plan: 7 of 15 complete (13-01, 13-02, 13-03, 13-04, 13-05, 13-06, 13-09) — next: waves 3+
 Status: Executing Phase 13
-Last activity: 2026-08-04 — 13-09 complete (nginx sync + CSP browser verification on archi-dev-box)
+Last activity: 2026-08-04 — 13-04 complete (D-13 music model, lofty gate, tag extraction 7/7 green)
 
 Progress: [█████░░░░░] 54%
 
@@ -82,6 +82,8 @@ Progress: [█████░░░░░] 54%
 - [Phase 13, D-19 (2026-08-03)]: **AIUI's source migrated into this repo at `aiui/`**, via `git subtree` with its full 230-commit history (`7ba3109b`, from AIUI `development` @ `e30ac1d`). Supersedes D-15's two-repo premise and voids D-18 entirely. Retires the recurring "AIUI commit stranded local-only" failure (windows 4 and 17) — `e30ac1d` came across in the import and is now pushed. D-17 (standalone mode) is unaffected: archy has no root `package.json`, so AIUI's pnpm/turbo workspace does not collide. Consequence: plans **13-06, 13-09, 13-11** still target `/home/archipelago/Projects/AIUI/` absolute paths and must be re-planned before wave 2; 13-09's `scripts/aiui.pin` deliverable is now meaningless for an in-repo directory.
 - [Phase 13, wave 1]: Recovered from a broken-pipe interruption that left 13-01 and 13-02 executor work uncommitted in orphaned worktrees. Both were checkpointed verbatim before any agent touched them, then re-committed atomically per task by continuation executors (both chose `reset --soft` + recommit). 13-03 was already complete and was fast-forwarded in.
 - [Phase 13, execution mode]: `parallelization: false` — this 4-core box thrashed (load 35-55, 15G/23G swap) running two worktree cargo builds concurrently alongside a live node (bitcoind/electrumx/lnd). Serial execution is strictly faster here.
+- [Phase 13, 13-04 / D-13 one-way half (2026-08-04, operator)]: Music entity model recorded in 13-MUSIC-MODEL.md BEFORE any node indexes a library — hybrid-identity ((source, canonical path) row key + lazily-backfilled content-hash dedupe column), derived-albums (albums/artists computed at read time, never stored rows), index-format-json (data_dir/music/index.json, content_server.rs precedent), sources = both OwnLibrary and Peer. MUSIC_SCHEMA_VERSION starts at 1; an older binary treats a newer-versioned index as absent (log + empty in-memory index, never overwrite) until an explicit reindex.
+- [Phase 13, 13-04 Task 2 (2026-08-04, operator)]: lofty 0.24.0 approved through the blocking-human package-legitimacy gate ([ASSUMED] in 13-RESEARCH.md's audit); dep tree reviewed, no networking crates. Media-root confinement in extract_tags is a parameter (media_roots), checked via canonicalize before any file open (T-13-20).
 
 Decisions are logged in PROJECT.md (10 locked ADRs in the `<decisions>` block + milestone decisions table). Recent decisions affecting current work: