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/main/overlay-visibility-runtime.ts

@@ -4,6 +4,8 @@ import type { BaseWindowTracker } from '../window-trackers';
 import type { WindowGeometry } from '../types';
 import { updateVisibleOverlayVisibility } from '../core/services';
 
+const OVERLAY_LOADING_OSD_COOLDOWN_MS = 30_000;
+
 export interface OverlayVisibilityRuntimeDeps {
   getMainWindow: () => BrowserWindow | null;
   getVisibleOverlayVisible: () => boolean;
@@ -29,6 +31,8 @@ export interface OverlayVisibilityRuntimeService {
 export function createOverlayVisibilityRuntimeService(
   deps: OverlayVisibilityRuntimeDeps,
 ): OverlayVisibilityRuntimeService {
+  let lastOverlayLoadingOsdAtMs: number | null = null;
+
   return {
     updateVisibleOverlayVisibility(): void {
       updateVisibleOverlayVisibility({
@@ -50,6 +54,15 @@ export function createOverlayVisibilityRuntimeService(
         isMacOSPlatform: deps.isMacOSPlatform(),
         isWindowsPlatform: deps.isWindowsPlatform(),
         showOverlayLoadingOsd: (message: string) => deps.showOverlayLoadingOsd(message),
+        shouldShowOverlayLoadingOsd: () =>
+          lastOverlayLoadingOsdAtMs === null ||
+          Date.now() - lastOverlayLoadingOsdAtMs >= OVERLAY_LOADING_OSD_COOLDOWN_MS,
+        markOverlayLoadingOsdShown: () => {
+          lastOverlayLoadingOsdAtMs = Date.now();
+        },
+        resetOverlayLoadingOsdSuppression: () => {
+          lastOverlayLoadingOsdAtMs = null;
+        },
         resolveFallbackBounds: () => deps.resolveFallbackBounds(),
       });
     },

src/main/runtime/stats-cli-command.test.ts

@@ -75,6 +75,29 @@ test('stats cli command starts tracker, server, browser, and writes success resp
   ]);
 });
 
+test('stats cli command respects stats.autoOpenBrowser=false', async () => {
+  const { handler, calls, responses } = makeHandler({
+    getResolvedConfig: () => ({
+      immersionTracking: { enabled: true },
+      stats: { serverPort: 6969, autoOpenBrowser: false },
+    }),
+  });
+
+  await handler({ statsResponsePath: '/tmp/subminer-stats-response.json' }, 'initial');
+
+  assert.deepEqual(calls, [
+    'ensureImmersionTrackerStarted',
+    'ensureStatsServerStarted',
+    'info:Stats dashboard available at http://127.0.0.1:6969',
+  ]);
+  assert.deepEqual(responses, [
+    {
+      responsePath: '/tmp/subminer-stats-response.json',
+      payload: { ok: true, url: 'http://127.0.0.1:6969' },
+    },
+  ]);
+});
+
 test('stats cli command starts background daemon without opening browser', async () => {
   const { handler, calls, responses } = makeHandler({
     ensureBackgroundStatsServerStarted: () => {