refactor(core): decompose remaining oversized hotspots with seam coverage

# Conflicts:
#	src/config/service.ts

backlog/tasks/task-85 - Refactor-large-files-for-maintainability-and-readability.md

@@ -4,7 +4,7 @@ title: Refactor large files for maintainability and readability
 status: In Progress
 assignee: []
 created_date: '2026-02-19 09:46'
-updated_date: '2026-02-20 11:42'
+updated_date: '2026-02-21 03:29'
 labels:
   - architecture
   - refactor
@@ -45,6 +45,9 @@ Several core files are oversized and high-coupling (`src/main.ts`, `src/anki-int
 - 2026-02-20: Large `src/main.ts` composition slices extracted into runtime handler modules (startup, CLI, tray/window/bootstrap, shortcuts, OSD/secondary-sub, numeric/overlay shortcut lifecycle, and related seams) with focused parity tests.
 - 2026-02-20: `src/anki-integration.ts` constructor decomposed into targeted private factory/config methods (`normalizeConfig`, `createKnownWordCache`, `createPollingRunner`, `createCardCreationService`, `createFieldGroupingService`) to reduce orchestration complexity.
 - 2026-02-20: `src/config/service.ts` load/apply duplication reduced by introducing `applyResolvedConfig`, `resolveExistingConfigPath`, and `parseConfigContent`.
+- 2026-02-20: added `src/main/runtime/domains/*` barrels plus `src/main/runtime/registry.ts`; migrated `src/main.ts` runtime import paths to domain barrels and added `check:main-fanin` guardrail script.
+- 2026-02-21: extracted additional `src/main.ts` deps-builder orchestration into composer modules (`jellyfin-remote`, `anilist-setup`) with focused tests; tightened main fan-in guard (`<=110` import lines, `<=11` unique paths).
+- Remaining gap for TASK-85/TASK-94: continue composer extraction for startup/overlay/ipc/shortcuts to reach fully thin composition root.
 - Validation checkpoint: `bun run build` and focused suites (`dist/config/config.test.js`, `dist/anki-integration.test.js`) passing.
 - Current strategy: prioritize high-ROI extractions (behavioral seams and churn-heavy hotspots) over further low-impact micro-shuffles.
 <!-- SECTION:PROGRESS:END -->
@@ -52,15 +55,27 @@ Several core files are oversized and high-coupling (`src/main.ts`, `src/anki-int
 ## Acceptance Criteria
 <!-- AC:BEGIN -->
 - [ ] #1 `src/main.ts` reduced to orchestration-focused module with extracted runtime domains
-- [ ] #2 `src/anki-integration.ts` reduced to facade with helper collaborators
-- [ ] #3 Config and immersion tracker services decomposed without behavior regressions
+- [x] #2 `src/anki-integration.ts` reduced to facade with helper collaborators
+- [x] #3 Config and immersion tracker services decomposed without behavior regressions
 - [ ] #4 `subminer` generated artifact ownership/workflow documented and enforced
-- [ ] #5 Full build + config/core tests pass after refactor
+- [x] #5 Full build + config/core tests pass after refactor
 <!-- AC:END -->
 
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+TASK-95 completion slice evidence: decomposed hotspot collaborators and reduced LOC across all remaining core hotspots.
+
+TASK-95 LOC deltas: `src/anki-integration.ts` -407 (1722 -> 1315), `src/config/service.ts` -1492 (1591 -> 99), `src/core/services/immersion-tracker-service.ts` -361 (1470 -> 1109).
+
+TASK-95 extracted collaborators: `src/anki-integration/field-grouping-merge.ts`, `src/config/{load.ts,parse.ts,warnings.ts,resolve.ts}`, `src/core/services/immersion-tracker/{types.ts,reducer.ts,queue.ts,maintenance.ts,query.ts}`.
+
+TASK-95 verification evidence: `bun run build`, `bun run test:config:dist`, `bun run test:core:dist`, `bun run check:file-budgets` completed with no failing tests.
+<!-- SECTION:NOTES:END -->
+
 ## Definition of Done
 <!-- DOD:BEGIN -->
 - [ ] #1 Plan at `docs/plans/2026-02-19-repo-maintainability-refactor-plan.md` executed or decomposed into child tasks
-- [ ] #2 Regression coverage added for extracted seams
+- [x] #2 Regression coverage added for extracted seams
 - [ ] #3 Docs updated for architecture and contributor workflow changes
 <!-- DOD:END -->