refactor(main): extract anilist/mpv runtime composers

backlog/tasks/task-71 - Split-main.ts-into-domain-runtime-modules-round-2.md

@@ -1,10 +1,11 @@
 ---
 id: TASK-71
 title: Split main.ts into domain runtime modules round 2
-status: In Progress
-assignee: []
+status: Done
+assignee:
+  - codex
 created_date: '2026-02-18 11:35'
-updated_date: '2026-02-21 03:40'
+updated_date: '2026-02-21 04:57'
 labels:
   - architecture
   - refactor
@@ -45,14 +46,48 @@ priority: high
 
 ## Acceptance Criteria
 <!-- AC:BEGIN -->
-- [ ] #1 `src/main.ts` responsibilities reduced to composition/wiring concerns
-- [ ] #2 Extracted runtime modules have focused interfaces and isolated tests
-- [ ] #3 No CLI/IPC regressions in existing test suite
-- [ ] #4 Docs reflect new module boundaries
+- [x] #1 `src/main.ts` responsibilities reduced to composition/wiring concerns
+- [x] #2 Extracted runtime modules have focused interfaces and isolated tests
+- [x] #3 No CLI/IPC regressions in existing test suite
+- [x] #4 Docs reflect new module boundaries
 <!-- AC:END -->
 
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1) Extract AniList tracking composition from src/main.ts (refresh/guess/probe/retry/update handler assembly) into src/main/runtime/composers/anilist-tracking-composer.ts with focused seam tests.
+2) Extract MPV runtime composition from src/main.ts (bind event handlers, MPV client factory, subtitle render metrics, tokenizer warmups) into src/main/runtime/composers/mpv-runtime-composer.ts with focused seam tests.
+3) Rewire src/main.ts to consume both composers while preserving existing local helper contracts and downstream behavior.
+4) Update architecture docs to reflect composition boundary under src/main/runtime/composers/*.
+5) Run verification gate (build + check:main-fanin + test:core:dist), then record TASK-71 notes/AC/DoD and finalize if green.
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+2026-02-21: extracted two remaining high-noise main-process composition clusters from `src/main.ts` into dedicated runtime composers: `src/main/runtime/composers/anilist-tracking-composer.ts` (AniList media tracking/probe/retry/update assembly) and `src/main/runtime/composers/mpv-runtime-composer.ts` (MPV event binding/factory/metrics/tokenizer/warmups assembly).
+
+Rewired `src/main.ts` to consume composer outputs while preserving existing helper contracts/call sites (`refreshAnilistClientSecretState`, `processNextAnilistRetryUpdate`, `maybeRunAnilistPostWatchUpdate`, `createMpvClientRuntimeService`, `updateMpvSubtitleRenderMetrics`, `tokenizeSubtitle`, `startBackgroundWarmups`).
+
+Added focused seam tests: `src/main/runtime/composers/anilist-tracking-composer.test.ts` and `src/main/runtime/composers/mpv-runtime-composer.test.ts`.
+
+Added `src/main/runtime/composers/index.ts` barrel and updated main imports to keep runtime fan-in strict gate green.
+
+Docs updated for new boundaries in `docs/architecture.md` and `docs/development.md`.
+
+Verification: `bun run build`, `bun test src/main/runtime/composers/anilist-tracking-composer.test.ts src/main/runtime/composers/mpv-runtime-composer.test.ts`, `bun run check:main-fanin:strict` (85 import lines / 10 unique runtime paths, pass), and `bun run test:fast` (pass).
+
+`src/main.ts` LOC reduced from 2956 to 2875 in this pass.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Completed TASK-71 round 2 by extracting AniList tracking and MPV runtime assembly clusters out of `src/main.ts` into dedicated composer modules with focused seam tests, then rewiring the composition root to consume those modules without changing runtime behavior. Added a composers barrel to reduce runtime import fan-in and updated architecture/development docs to reflect composer-first boundaries; verification gates (`build`, `check:main-fanin:strict`, composer tests, `test:fast`) all pass.
+<!-- SECTION:FINAL_SUMMARY:END -->
+
 ## Definition of Done
 <!-- DOD:BEGIN -->
-- [ ] #1 `bun run test:fast` passes
-- [ ] #2 Architecture docs updated
+- [x] #1 `bun run test:fast` passes
+- [x] #2 Architecture docs updated
 <!-- DOD:END -->