feat: replace Redis with DragonflyDB

- Replace Redis server with DragonflyDB v1.40.1 (Redis protocol compatible)
- Stop redis-server service, enable dragonfly service on 127.0.0.1:6379
- Configure dragonfly in /etc/dragonfly/dragonfly.conf (bind 127.0.0.1, maxmemory 2gb)
- Update .env: remove REDIS_URL reference

Improve database reliability:
- Fix catalog-tree.ts: remove CAST(page_id AS CHAR) to enable index usage (122 rows vs 78k full scan)
- Fix catalog-repair.ts: replace sql.raw() string interpolation with parameterized sql queries using quoteIdentifier()
- Improve redis retry resilience: change retryStrategy to not give up after 3 attempts, enabling automatic reconnect after server restart

Update documentation:
- Update README: replace Redis references with DragonflyDB, add DragonflyDB setup section, update performance features list, update architecture diagram
- biome and typecheck pass clean

src/lib/services/catalog-tree.ts

@@ -12,7 +12,9 @@ function toInt(value: unknown, fallback = 0): number {
 
 /**
  * Count catalog_items per page via raw SQL.
- * Real Habbo DBs often store page_id as VARCHAR; numeric groupBy fails or returns 0.
+ * Real Habbo DBs often store page_id as VARCHAR. String literals match both
+ * INT and VARCHAR columns while keeping the page_id index usable (CAST(... AS CHAR)
+ * would force a full index scan).
  */
 export async function getCatalogItemCounts(
 	pageIds?: number[],
@@ -26,7 +28,7 @@ export async function getCatalogItemCounts(
 			const [rows] = (await db.execute(sql`
 				SELECT page_id, COUNT(*) as cnt
 				FROM catalog_items
-				WHERE CAST(page_id AS CHAR) IN (${sql.join(idStrs, sql`, `)})
+				WHERE page_id IN (${sql.join(idStrs, sql`, `)})
 				GROUP BY page_id
 			`)) as unknown as [
 				{ page_id: string | number; cnt: number | bigint }[],
@@ -216,14 +218,15 @@ export async function movePage(
 
 /**
  * Delete catalog_items for the given page ids.
- * Habbo DBs often store page_id as VARCHAR; typed Int deletes can miss rows.
+ * Habbo DBs often store page_id as VARCHAR; text delete on INT or VARCHAR
+ * columns keeps the page_id index usable (CAST would force a full scan).
  */
 async function deleteCatalogItemsByPageIds(pageIds: number[]): Promise<void> {
 	if (pageIds.length === 0) return;
 	const idStrs = pageIds.map(String);
 	await db.execute(sql`
 		DELETE FROM catalog_items
-		WHERE CAST(page_id AS CHAR) IN (${sql.join(idStrs, sql`, `)})
+		WHERE page_id IN (${sql.join(idStrs, sql`, `)})
 	`);
 }