feat: add automatic media normalization, R2 retention cleanup, and seamless playout loops

.github/instructions/BACKLOG.md

@@ -1,34 +1,14 @@
 # BACKLOG
 
-## Remaining from 2026-08-11 (summary)
-
-- **Test Fixtures**: media + playlist fixtures created; ffmpeg generation commands documented in test headers
-- **User Frontend Tests**: video player, chat integration, responsive, accessibility, coverage
-- **Admin Frontend Tests**: playlist UI, moderation UI, metrics dashboards, coverage
-- **Cloudflare R2 Integration Test**: upload + cache header validation done (SyncToR2 with CacheControl + ContentType); edge cache hit/miss validation remains manual
-- **Cloudflare Config**: Cloudflare Pages deploy workflow and setup docs created; manual dashboard setup (Tiered Cache, WAF, rate limiting, HTTPS/HSTS) remains pending; Pages project must be created in dashboard first.
-- **External Services**: UptimeRobot monitors + alerts
-- **Production Deployment**: Hetzner provisioning, CD pipeline, DNS cutover, smoke test
-- **Scaling & Performance**: TTFB baseline and live benchmark runs still pending; loadtest scaffolding now includes Artillery/k6 helpers with auto summaries plus worksheet field mapping; chat p95, Redis saturation, and cache-hit threshold alerting are implemented
+> All remaining work is planned in [TODO](./TODO.md) (2026-08-13). This file records completed backlog items for reference; new unplanned work is added here.
 
 ## Cloudflare Configuration
 
 ### DNS & Pages
 
-- [x] Configure DNS for linearvoid.tv apex and www redirect (manual)
-- [x] Configure media.linearvoid.tv for split-domain HLS delivery (manual)
-- [x] Configure Cloudflare Pages deploy workflow (`.gitea/workflows/pages-deploy.yml`) and setup docs (`docs/operations/cloudflare-pages-setup.md`, `docs/operations/gitea-cloudflare-pages.md`)
-- [x] Create Cloudflare Pages project in dashboard (unavailable, created `linearvoid` via API)
 - [ ] Cloudflare Pages: link custom domain (manual)
 - [ ] Create Cloudflare Pages project and cut over frontend hosting (manual)
 
-### Storage & Cache
-
-- [x] Create R2 bucket (manual)
-- [x] Configure Cache Rules: .ts/.m4s + .m3u8 (manual)
-- [x] Implement Worker for immutable cache headers on segment paths
-- [ ] CORS headers on HLS responses from media.linearvoid.tv (MEDIUM) — needs Cloudflare R2 CORS config
-
 ### Security & TLS
 
 - [ ] Enable Tiered Cache, WAF, rate limiting (manual)
@@ -40,13 +20,6 @@
 
 ## Monitoring & Observability
 
-### Prometheus & Grafana
-
-- [x] Set up Prometheus with chat/playout/nginx/redis/postgres/node scrape targets
-- [x] Add nginx-exporter, redis-exporter, postgres-exporter, node-exporter
-- [x] Import Grafana app + operational dashboards
-- [x] Define Prometheus alerting rules (8 rules: ChatDown, PlayoutDown, RedisDown, etc.)
-
 ### External Monitoring
 
 - [ ] Set up UptimeRobot external monitoring
@@ -54,44 +27,16 @@
 - [ ] UptimeRobot: add keyword monitor for `https://linearvoid.tv/hls/playlist.m3u8` (keyword: `#EXTM3U`, 5min)
 - [ ] Alert on 2 consecutive failures, notify via email + Discord/Slack webhook
 
-## Security
-
-- [x] Implement admin cookie-session auth (HttpOnly, SameSite=Strict, Secure when TLS)
-- [x] Implement server-side session expiration
-- [x] Implement rate limiting for chat messages (Redis windowing)
-- [x] Implement WebSocket connection rate limiting (5/IP/60s)
-- [x] Implement admin login rate limiting (5/IP/5min)
-- [ ] Enforce HTTPS/WSS at edge and origin
-
-## Test Fixtures
-
-- [x] Create test media fixtures in `backend/playout/testdata/`: valid H.264/AAC, invalid codec, invalid framerate
-- [x] Create test playlist fixtures: `valid_playlist.txt`, `empty_playlist.txt`, `comments_only.txt`, `mixed_valid_invalid.txt`
-- [x] Document ffmpeg fixture-generation commands in test file headers
-
 ## Frontend Tests
 
 ### User Frontend
 
-- [x] Video player behavior (play, pause, seek, buffering, error handling) — HLS player startup, native/fallback, URL resolution, error recovery with retries/backoff/reconnecting overlay
-- [x] Chat functionality (send/receive messages, presence, rate limiting, moderation) — send, receive, presence join/leave, DM flow, reconnect covered
-- [x] State management and data flow
-- [x] Responsive design and layout across different screen sizes — chat-collapsed toggle, CSS grid, now-playing aria
-- [x] Accessibility testing (keyboard navigation, screen reader support) — video controls, aria-labels, aria-expanded, input labels, reconnecting overlay aria-live/role
-- [x] Integration with backend APIs (mocking API responses for testing)
 - [ ] Test coverage for all critical frontend components and interactions
 - [ ] Add code coverage reporting and enforce minimum coverage threshold in CI/CD pipeline
 - [ ] Document test cases and expected outcomes
 
 ### Admin Frontend
 
-- [x] Playlist management UI (add/remove videos, reorder, normalize) — save/error handling, sortable rendering
-- [ ] User moderation tools (mute/ban/report users, view moderation logs)
-- [x] Metrics and monitoring dashboards (Prometheus/Grafana integration) — overview + analytics rendering
-- [x] State management and data flow
-- [x] Responsive design and layout across different screen sizes — tab content visibility, essential tabs
-- [x] Accessibility testing (keyboard navigation, screen reader support) — nav aria-label, active tab aria-current, nav button focusability
-- [x] Integration with backend APIs (mocking API responses for testing)
 - [ ] Test coverage for all critical admin UI components and interactions
 - [ ] Add code coverage reporting and enforce minimum coverage threshold in CI/CD pipeline
 - [ ] Document test cases and expected outcomes
@@ -100,29 +45,9 @@
 
 ### Cloudflare R2
 
-- [x] Upload test HLS segments and manifests to R2 bucket (SyncToR2 with mock, verified bucket/key/body)
-- [x] Verify correct cache headers are applied (immutable segments via segmentCacheControl, short-lived manifests via manifestCacheControl)
 - [ ] Test retrieval of segments and manifests from R2 via Cloudflare edge
 - [ ] Validate cache hit/miss behavior and performance metrics
 - [ ] Validate edge cache hit/miss behavior with repeat requests — script `scripts/validate-edge-cache.sh` created
-- [x] Ensure integration test can run in CI/CD pipeline with proper mocking/stubbing of R2 API (putObject mock, no network calls)
-- [x] Document test cases and expected outcomes
-- [x] Document required stubs or mocks (putObject variable injection pattern)
-
-## Streaming Pipeline
-
-- [x] **Continuous R2 sync during playout (HIGH)**: fsnotify watcher uploads segments in real-time (~7s delay)
-- [x] **Globally unique segment naming (HIGH)**: `r-{ISOTIME}/seg-{seq}.m4s` via run ID + ffmpeg monotonic sequence
-- [x] **Atomic manifest publication (MEDIUM)**: Upload to `playlist.m3u8.tmp`, then `CopyObject` to final key
-- [x] **Manifest Cache-Control alignment (LOW)**: `public, max-age=1, s-maxage=2, must-revalidate`
-- [ ] **CORS headers on HLS responses (MEDIUM)**: Needs Cloudflare R2 bucket CORS config (infrastructure, not code)
-- [x] **Player error recovery (MEDIUM)**: `hls.on(Hls.Events.ERROR)` handler with bounded retries (5x), exponential backoff, reconnecting overlay
-- [x] **Health endpoint detail (LOW)**: Added active item, run ID, playlist revision, last segment seq, last R2 pub, consecutive failures
-- [x] Source media contract + validation (H.264/AAC, 30fps, keyframe check)
-- [x] fMP4 HLS packaging (6s segments, 24 window)
-- [x] Slate fallback + recovery (`shouldEscalateToSlate`)
-- [x] R2 cache headers (immutable segments, short-lived manifest)
-- [x] Cloudflare Worker immutable `.m4s` headers
 
 ## External Services
 
@@ -162,9 +87,6 @@
 
 ### Load Testing
 
-- [x] Load-test scaffolding: `ws-chat.yml`, `admin-api.js`, `run-loadtests.ps1`, summarizers, README
-- [x] Cache-hit ratio exporter (`scripts/cache-hit-ratio.js` + `.ps1`)
-- [x] Saturation alerts: chat p95 latency, Redis memory usage, cache-hit ratio
 - [ ] Execute WebSocket load tests with real infrastructure — ramp 10→100→500→1000 connections, measure p95 latency + errors
 - [ ] Execute admin API benchmarks with real infrastructure — `wrk`/`k6` against `/api/admin/*`, target p95 <1s