fix: verbose error handling, batch processing, and multi-file support

- Replace [object Object] errors with readable messages across all 20+ API
  routes by normalizing Zod validation errors to strings (formatZodErrors)
- Add parseApiError() on frontend to defensively handle any details type
- Add global Fastify error handler with full stack traces in logs
- Fix image-to-pdf auth: Object.entries(headers) → headers.forEach()
- Fix passport-photo: safeParse + formatZodErrors, safe error extraction
- Fix OCR silent fallbacks: log exception type/message when falling back,
  include actual engine used in API response and Docker logs
- Fix split tool: process all uploaded images, combine into ZIP with
  subfolders per image
- Fix batch support for blur-faces, strip-metadata, edit-metadata,
  vectorize: add processAllFiles branch for multi-file uploads
- Docker: LOG_LEVEL=debug, PYTHONWARNINGS=default for visibility
- Add Playwright e2e tests verifying all fixes against Docker container

apps/api/src/routes/tools/passport-photo.ts

@@ -7,6 +7,7 @@ import type { FastifyInstance, FastifyReply, FastifyRequest } from "fastify";
 import sharp from "sharp";
 import { z } from "zod";
 import { autoOrient } from "../../lib/auto-orient.js";
+import { formatZodErrors } from "../../lib/errors.js";
 import { validateImageBuffer } from "../../lib/file-validation.js";
 import { decodeHeic } from "../../lib/heic-converter.js";
 import { createWorkspace, getWorkspacePath } from "../../lib/workspace.js";
@@ -275,15 +276,14 @@ export function registerPassportPhoto(app: FastifyInstance) {
   app.post(
     "/api/v1/tools/passport-photo/generate",
     async (request: FastifyRequest, reply: FastifyReply) => {
-      let parsed: z.infer<typeof generateSettingsSchema>;
-      try {
-        parsed = generateSettingsSchema.parse(request.body);
-      } catch (err) {
+      const parseResult = generateSettingsSchema.safeParse(request.body);
+      if (!parseResult.success) {
         return reply.status(400).send({
           error: "Invalid settings",
-          details: err instanceof Error ? err.message : String(err),
+          details: formatZodErrors(parseResult.error.issues),
         });
       }
+      const parsed = parseResult.data;
 
       const {
         jobId,