fix: improve AI tool reliability for face detection and background removal (#25)

- Replace OpenCV Haar Cascades with MediaPipe for face detection, using
  short-range model first with full-range fallback for better accuracy
- Add auto-orient to remove-background route for EXIF-rotated photos
- Change default background removal model from u2net to birefnet-general-lite
- Fix flaky test by setting SQLite busy_timeout before journal_mode pragma

Co-authored-by: Siddharth Kumar Sah <siddharth123sk@gmail.com>

apps/api/src/routes/tools/blur-faces.ts

@@ -10,10 +10,7 @@ import { createWorkspace } from "../../lib/workspace.js";
 import { updateSingleFileProgress } from "../progress.js";
 import { registerToolProcessFn } from "../tool-factory.js";
 
-/**
- * Face detection and blurring route.
- * Uses MediaPipe for detection, PIL for blurring.
- */
+/** Face detection and blurring route. */
 export function registerBlurFaces(app: FastifyInstance) {
   app.post("/api/v1/tools/blur-faces", async (request: FastifyRequest, reply: FastifyReply) => {
     let fileBuffer: Buffer | null = null;