Enhance database performance: add cache size and temp store settings; refactor alert clearing statement

web/server/db.js

@@ -16,6 +16,8 @@ const db = new Database(DB_PATH);
 db.pragma('journal_mode = WAL');
 db.pragma('synchronous = NORMAL');
 db.pragma('foreign_keys = ON');
+db.pragma('cache_size = -8000');  // 8MB cache
+db.pragma('temp_store = MEMORY');
 
 // ========== Schema ==========
 
@@ -112,6 +114,7 @@ const getState = db.prepare(`SELECT value FROM state WHERE key = ?`);
 const getAllItems = db.prepare(`SELECT name, count, display_name as displayName FROM items ORDER BY count DESC`);
 const getAllFurnaces = db.prepare(`SELECT * FROM furnaces`);
 const getAllAlerts = db.prepare(`SELECT item, triggered, current, threshold FROM alerts WHERE triggered = 1`);
+const clearAlertTriggered = db.prepare(`UPDATE alerts SET triggered = 0`);
 
 const getItemHistory = db.prepare(`
   SELECT count, recorded_at as recordedAt
@@ -165,7 +168,7 @@ const saveFurnacesBatch = db.transaction((furnaces, now) => {
 
 const saveAlertsBatch = db.transaction((alerts, now) => {
   // Clear old triggered status
-  db.prepare('UPDATE alerts SET triggered = 0').run();
+  clearAlertTriggered.run();
   for (const alert of alerts) {
     upsertAlert.run({
       item: alert.item || '',