feat: add persistent lifetime stats and sync achievements

- Add lifetime stats persistence to Rust backend
- Sync achievement state between frontend and backend on startup
- Add commands for loading/saving stats to disk
- Expand achievement definitions with 150+ new achievements
- Fix stats store to properly track total vs session metrics

src/lib/stores/stats.ts

@@ -104,10 +104,11 @@ export async function initStatsListener() {
     stats.set(newStats);
   });
 
-  // Load initial stats from backend
+  // Load initial persisted stats from backend (no bridge required)
   try {
-    const initialStats = await invoke<UsageStats>("get_usage_stats");
+    const initialStats = await invoke<UsageStats>("get_persisted_stats");
     stats.set(initialStats);
+    console.log("Loaded persisted stats:", initialStats);
   } catch (error) {
     console.error("Failed to load initial stats:", error);
   }