fix(database): enable WAL mode and busy_timeout on every DB connection

Applies WAL journal, 5s busy_timeout, synchronous=NORMAL, and
foreign_keys=ON pragmas immediately after opening each connection so
concurrent main+worker writers share the same locking configuration
and avoid SQLITE_BUSY under contention.

src/main/database-base.ts

@@ -378,7 +378,12 @@ export class AppDatabaseBase {
   }
 
   protected openConnection(): DatabaseSync {
-    return new DatabaseSync(this.dbPath, { timeout: 5000 });
+    const db = new DatabaseSync(this.dbPath, { timeout: 5000 });
+    db.exec("pragma journal_mode = WAL;");
+    db.exec("pragma busy_timeout = 5000;");
+    db.exec("pragma synchronous = NORMAL;");
+    db.exec("pragma foreign_keys = ON;");
+    return db;
   }
 
   protected transaction<T>(operation: () => T): T {