feat(stats): add launcher stats command and build integration

- Launcher stats subcommand with cleanup mode
- Stats frontend build integrated into Makefile
- CI workflow updated for stats package
- Config example updated with stats section
- mpv plugin menu entry for stats toggle

README.md

@@ -27,6 +27,7 @@ SubMiner is an Electron overlay that sits on top of mpv. It turns your video pla
 - **Look up words as you watch** — Yomitan dictionary popups on hover or keyboard-driven token-by-token navigation
 - **One-key Anki mining** — Creates cards with sentence, audio, screenshot, and translation; optional local AnkiConnect proxy auto-enriches Yomitan cards instantly
 - **Reading annotations** — N+1 targeting, frequency-dictionary highlighting, JLPT underlining, and character name dictionary for anime/manga proper nouns
+- **Immersion stats** — Optional dashboard for watch time, sessions, trends, vocabulary, and mining throughput
 - **Subtitle tools** — Download from Jimaku, sync with alass/ffsubsync
 - **Jellyfin & AniList integration** — Remote playback, cast device mode, and automatic episode progress tracking
 - **Texthooker & API** — Built-in texthooker page and annotated websocket feed for external clients
@@ -118,7 +119,7 @@ Windows builds use native window tracking and do not require the Linux composito
 
 ## Documentation
 
-For full guides on configuration, Anki, Jellyfin, and more, see [docs.subminer.moe](https://docs.subminer.moe). The VitePress source for that site lives in [`docs-site/`](./docs-site/).
+For full guides on configuration, Anki, Jellyfin, immersion tracking/stats, and more, see [docs.subminer.moe](https://docs.subminer.moe). The VitePress source for that site lives in [`docs-site/`](./docs-site/).
 
 ## Acknowledgments