feat: stats and achievements (#45)

### Explanation

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### Issue

Closes #39

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### Tests

- [ ] My contribution adds new code, and I have added tests to cover it.
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Reviewed-on: #45
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

src-tauri/src/commands.rs

@@ -2,7 +2,9 @@ use tauri::{AppHandle, State};
 use tauri_plugin_store::StoreExt;
 
 use crate::config::{ClaudeStartOptions, HikariConfig};
+use crate::stats::UsageStats;
 use crate::wsl_bridge::SharedBridge;
+use crate::achievements::{load_achievements, get_achievement_info, AchievementUnlockedEvent};
 
 const CONFIG_STORE_KEY: &str = "config";
 
@@ -72,3 +74,29 @@ pub async fn save_config(app: AppHandle, config: HikariConfig) -> Result<(), Str
 
     Ok(())
 }
+
+#[tauri::command]
+pub async fn get_usage_stats(bridge: State<'_, SharedBridge>) -> Result<UsageStats, String> {
+    let bridge = bridge.lock();
+    Ok(bridge.get_stats())
+}
+
+#[tauri::command]
+pub async fn load_saved_achievements(app: AppHandle) -> Result<Vec<AchievementUnlockedEvent>, String> {
+    use chrono::Utc;
+
+    // Load achievements from persistent store
+    let progress = load_achievements(&app).await;
+
+    // Create events for all previously unlocked achievements
+    let mut events = Vec::new();
+    for achievement_id in &progress.unlocked {
+        let mut info = get_achievement_info(achievement_id);
+        info.unlocked_at = Some(Utc::now()); // We don't store timestamps, so just use now
+        events.push(AchievementUnlockedEvent {
+            achievement: info,
+        });
+    }
+
+    Ok(events)
+}