feat(01-01): configure Drizzle schema with entries table

- Schema with unified entries table (task/thought types)
- Fields: id, title, content, type, status, pinned, dueDate, timestamps
- Database connection with WAL mode
- Drizzle kit scripts (db:generate, db:migrate, db:push, db:studio)
- Database file at ./data/taskplaner.db

.gitignore

@@ -21,3 +21,6 @@ Thumbs.db
 # Vite
 vite.config.js.timestamp-*
 vite.config.ts.timestamp-*
+
+# Database
+/data/