feat(core): add Discord Rich Presence integration

Introduce optional Discord activity updates across config, runtime, tests, and docs so playback context appears in Discord without destabilizing app lifecycle. Tune default refresh cadence to reduce pause/resume lag during real sessions.

backlog/tasks/task-109 - Add-Discord-Rich-Presence-integration-with-polished-activity-card.md

@@ -2,9 +2,10 @@
 id: TASK-109
 title: Add Discord Rich Presence integration with polished activity card
 status: In Progress
-assignee: []
+assignee:
+  - opencode
 created_date: '2026-02-22 19:40'
-updated_date: '2026-02-22 22:36'
+updated_date: '2026-02-23 01:15'
 labels:
   - feature
   - discord
@@ -40,6 +41,16 @@ Add optional Discord Rich Presence support so SubMiner can publish current activ
 - [ ] #5 Docs include setup steps (app/client id), config keys, and troubleshooting notes.
 <!-- AC:END -->
 
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1) Validate existing TASK-109 implementation in working tree against AC #1-#5 (config default-off, activity mapping/transitions, polished visuals, resilient error handling, docs coverage).
+2) Run parallel audit passes (config/docs and runtime/lifecycle) and apply minimal fixes only for confirmed gaps.
+3) Execute focused Discord/config tests, then full gates (`bun run build`, `bun run test:fast`, `bun run docs:build`) and record outcomes.
+4) Capture manual Discord-session verification status/evidence.
+5) Finalize TASK-109 in Backlog with checked AC/DoD, final summary, and status Done (no commit).
+<!-- SECTION:PLAN:END -->
+
 ## Implementation Notes
 
 <!-- SECTION:NOTES:BEGIN -->
@@ -52,6 +63,12 @@ Wired MPV/runtime lifecycle hooks to refresh Discord presence on subtitle/media/
 Updated docs and generated config examples with Discord Rich Presence setup/config/troubleshooting guidance.
 
 Validation status: focused config/runtime/discord tests pass and docs build passes. Full `bun run build` currently blocked by pre-existing `src/main.ts` duplicate imports/symbol errors unrelated to TASK-109 scope (existing in working tree).
+
+User validation feedback: Discord activity resumed to Playing but with noticeable delay after pause/resume transitions.
+
+Adjusted default `discordPresence.updateIntervalMs` from `15000` to `3000` to reduce perceived status refresh lag while keeping debounce/duplicate suppression behavior unchanged.
+
+Updated docs/config examples (`docs/configuration.md`, `config.example.jsonc`, `docs/public/config.example.jsonc`) and config default assertions; reran focused tests: `bun test src/config/config.test.ts src/config/resolve/jellyfin.test.ts` and `bun test src/core/services/discord-presence.test.ts` (all pass).
 <!-- SECTION:NOTES:END -->
 
 ## Definition of Done