Add per-task-type submission configuration with client-side movie spec checks

Coordinators can configure, per task type, accepted file extensions, a
naming convention, and (for video files) required resolution/format/
codec/frame rate. All checking happens entirely client-side in the
browser before upload - the backend only stores and validates the
configuration itself, never inspects submitted files.

- backend: submission_config_by_task_type JSON column on Project,
  schemas/submission_config.py for validation, GET/PUT
  /projects/{id}/submission-config endpoints. Added .mxf/.ma/.usd(a/c)
  to the supported file formats.
- frontend: new Submissions tab in Project Settings
  (SubmissionConfigManager.vue) to configure rules per task type.
  TaskSubmissions.vue enforces them before upload: extension/naming
  checks via regex, and real video resolution/codec/frame rate
  detection via mediainfo.js (parses container metadata directly,
  so it works for formats browsers can't play natively like MXF,
  ProRes, or DNxHD).

frontend/package.json

@@ -18,6 +18,7 @@
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-vue-next": "^0.294.0",
+    "mediainfo.js": "^0.3.7",
     "pinia": "^2.1.7",
     "reka-ui": "^2.6.1",
     "shadcn-vue": "^2.3.2",