feat(stats): add stats server, API endpoints, config, and Anki integration

- Hono HTTP server with 20+ REST endpoints for stats data
- Stats overlay BrowserWindow with toggle keybinding
- IPC channel definitions and preload bridge
- Stats config section (toggleKey, serverPort, autoStartServer, autoOpenBrowser)
- Config resolver for stats section
- AnkiConnect proxy endpoints (guiBrowse, notesInfo)
- Note ID passthrough in card mining callback chain
- Stats CLI command with autoOpenBrowser respect

src/config/definitions/defaults-stats.ts

@@ -0,0 +1,10 @@
+import { ResolvedConfig } from '../../types.js';
+
+export const STATS_DEFAULT_CONFIG: Pick<ResolvedConfig, 'stats'> = {
+  stats: {
+    toggleKey: 'Backquote',
+    serverPort: 5175,
+    autoStartServer: true,
+    autoOpenBrowser: true,
+  },
+};