Enable sqlite WAL and busy timeout

internal/matrixbot/state_store.go

@@ -33,7 +33,9 @@ func NewStateStore(path string) (*StateStore, error) {
 		return nil, fmt.Errorf("create state store dir: %w", err)
 	}
 
-	db, err := sql.Open("sqlite", path)
+	// Enable WAL mode + busy timeout to reduce SQLITE_BUSY errors under concurrency.
+	dsn := path + "?_pragma=busy_timeout(5000)&_pragma=journal_mode(WAL)"
+	db, err := sql.Open("sqlite", dsn)
 	if err != nil {
 		return nil, fmt.Errorf("open state store: %w", err)
 	}