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/ipc.ts

@@ -85,6 +85,12 @@ export interface IpcServiceDeps {
       activeDays: number;
       totalEpisodesWatched: number;
       totalAnimeCompleted: number;
+      totalTokensSeen: number;
+      totalLookupCount: number;
+      totalLookupHits: number;
+      totalYomitanLookupCount: number;
+      newWordsToday: number;
+      newWordsThisWeek: number;
     }>;
     getSessionTimeline: (sessionId: number, limit?: number) => Promise<unknown>;
     getSessionEvents: (sessionId: number, limit?: number) => Promise<unknown>;
@@ -486,8 +492,10 @@ export function registerIpcHandlers(deps: IpcServiceDeps, ipc: IpcMainRegistrar
           activeDays: 0,
           totalEpisodesWatched: 0,
           totalAnimeCompleted: 0,
+          totalTokensSeen: 0,
           totalLookupCount: 0,
           totalLookupHits: 0,
+          totalYomitanLookupCount: 0,
           newWordsToday: 0,
           newWordsThisWeek: 0,
         },