feat: implement archiving functionality for counters and update related logic

lib/db.ts

@@ -29,7 +29,8 @@ db.exec(`
     value       INTEGER NOT NULL DEFAULT 0,
     image_path  TEXT,
     group_id    INTEGER REFERENCES groups(id) ON DELETE SET NULL,
-    order_index INTEGER NOT NULL DEFAULT 0
+    order_index INTEGER NOT NULL DEFAULT 0,
+    archived_at INTEGER
   );
 
   CREATE TABLE IF NOT EXISTS events (
@@ -42,5 +43,11 @@ db.exec(`
   CREATE INDEX IF NOT EXISTS idx_events_date    ON events(created_at);
 `);
 
+// Incremental migrations
+const cols = (db.prepare("PRAGMA table_info(counters)").all() as { name: string }[]).map(c => c.name);
+if (!cols.includes('archived_at')) {
+  db.exec('ALTER TABLE counters ADD COLUMN archived_at INTEGER');
+}
+
 export { UPLOADS_DIR };
 export default db;