Fix stats command flow and tracking metrics regressions

- Route default `subminer stats` through attached `--stats`; keep daemon path for `--background`/`--stop`
- Update overview metrics: lookup rate uses lifetime Yomitan lookups per 100 tokens; new words dedupe by headword
- Suppress repeated macOS `Overlay loading...` OSD during fullscreen tracker flaps and improve session-detail chart scaling
- Add/adjust launcher, tracker query, stats server, IPC, overlay, and stats UI regression tests; add changelog fragments

src/core/services/immersion-tracker-service.ts

@@ -365,6 +365,12 @@ export class ImmersionTrackerService {
     totalActiveMin: number;
     totalCards: number;
     activeDays: number;
+    totalTokensSeen: number;
+    totalLookupCount: number;
+    totalLookupHits: number;
+    totalYomitanLookupCount: number;
+    newWordsToday: number;
+    newWordsThisWeek: number;
   }> {
     return getQueryHints(this.db);
   }