feat: close STREAMING.md production readiness gaps

- Added run ID + unique segment naming (r-{ISOTIME}/seg-{seq}.m4s)
- Added fsnotify watcher for real-time R2 segment upload (~7s)
- Added atomic manifest publication (temp key → CopyObject)
- Fixed manifest Cache-Control: public, max-age=1, s-maxage=2, must-revalidate
- Added hls.js error recovery: bounded retries (5x), exponential backoff, reconnecting UI
- Enriched /health endpoint: run_id, active_item, last_segment_seq, last_r2_pub, consecutive_failures, unhealthy detection
- Updated tests: HealthHandler (new fields + unhealthy), player error recovery test
- Updated TODO.md, BACKLOG.md, DONE.md, MEMORY.md

.github/instructions/DONE.md

@@ -970,3 +970,18 @@ Notes:
 - Configured runner labels (linux)
 - Set up runner auto-scaling (optional)
 - Configured runner logging and monitoring
+
+## Session 2026-08-10 — STREAMING.md Production Readiness
+
+Completed 6 of 7 streaming pipeline gaps from STREAMING.md contract audit:
+
+- [x] **Continuous R2 sync (HIGH)** — Added `watchAndPublishSegments()` using `fsnotify` to upload segments in real-time (~7s delay), replacing batch-on-exit pattern.
+- [x] **Globally unique segment naming (HIGH)** — Added `initRunID()` generating `r-ISOTIME` IDs and `seg-{seq}.m4s` monotonic naming. Replaced `strftime` collision-prone pattern.
+- [x] **Atomic manifest publication (MEDIUM)** — Added `publishManifest()` uploading to `playlist.m3u8.tmp` then `CopyObject` to final key.
+- [x] **Manifest Cache-Control contract (LOW)** — Updated to `public, max-age=1, s-maxage=2, must-revalidate`.
+- [x] **Player error recovery (MEDIUM)** — Added `hls.on(ERROR)` handler with bounded retries (5x), exponential backoff (2s→32s), reconnecting overlay with spinner.
+- [x] **Health endpoint detail (LOW)** — Enriched `/health` with `run_id`, `active_item`, `playlist_revision`, `last_segment_seq`, `last_r2_pub`, `consecutive_failures`, and `unhealthy` detection.
+- [ ] CORS on `media.linearvoid.tv` — Remaining infrastructure-only (Cloudflare R2 CORS configuration, not code).
+
+**Files changed:** `backend/playout/src/playlist.go` (+171/-35), `playlist_test.go` (+51/-7), `go.mod` (+2), `frontend/src/main.ts` (+76/-2), `main.test.ts` (+43/-1), `style.css` (+37), `index.html` (+5).
+**Tests:** HealthHandler tests updated for new fields + added Unhealthy test. Player error recovery test added. All existing tests preserved.