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).

backend/routers/projects.py

@@ -16,6 +16,7 @@ from schemas.project import (
     ProjectTechnicalSpecs, DeliveryMovieSpec, DEFAULT_DELIVERY_MOVIE_SPECS,
     ProjectSettings, ProjectSettingsUpdate, DEFAULT_ASSET_TASKS, DEFAULT_SHOT_TASKS
 )
+from schemas.submission_config import ProjectSubmissionConfig, SubmissionTypeConfig
 from utils.auth import get_current_user, require_role, get_current_user_from_token
 
 router = APIRouter()
@@ -1077,6 +1078,87 @@ async def delete_custom_task_type(
     return _build_all_task_types_response(db_project)
 
 
+# Submission Configuration Endpoints
+
+@router.get("/{project_id}/submission-config", response_model=ProjectSubmissionConfig)
+async def get_project_submission_config(
+    project_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user_with_db)
+):
+    """Get the project's per-task-type submission configuration"""
+    project = db.query(Project).filter(Project.id == project_id).first()
+
+    if not project:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Project not found"
+        )
+
+    if current_user.role == UserRole.ARTIST:
+        member = db.query(ProjectMember).filter(
+            ProjectMember.project_id == project_id,
+            ProjectMember.user_id == current_user.id
+        ).first()
+        if not member:
+            raise HTTPException(
+                status_code=status.HTTP_403_FORBIDDEN,
+                detail="Access denied to this project"
+            )
+
+    config_data = project.submission_config_by_task_type
+    if isinstance(config_data, str):
+        try:
+            config_data = json.loads(config_data)
+        except (json.JSONDecodeError, TypeError):
+            config_data = {}
+
+    return ProjectSubmissionConfig(config_by_task_type=config_data or {})
+
+
+@router.put("/{project_id}/submission-config", response_model=ProjectSubmissionConfig)
+async def update_project_submission_config(
+    project_id: int,
+    submission_config: ProjectSubmissionConfig,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_coordinator_or_admin)
+):
+    """Replace the project's per-task-type submission configuration"""
+    db_project = db.query(Project).filter(Project.id == project_id).first()
+
+    if not db_project:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Project not found"
+        )
+
+    all_types_response = _build_all_task_types_response(db_project)
+    valid_task_types = set(all_types_response.asset_task_types) | set(all_types_response.shot_task_types)
+    for task_type in submission_config.config_by_task_type.keys():
+        if task_type not in valid_task_types:
+            raise HTTPException(
+                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+                detail=f"'{task_type}' is not a valid task type for this project"
+            )
+
+    db_project.submission_config_by_task_type = {
+        task_type: config.dict()
+        for task_type, config in submission_config.config_by_task_type.items()
+    }
+
+    try:
+        db.commit()
+        db.refresh(db_project)
+    except Exception:
+        db.rollback()
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail="Failed to update submission configuration"
+        )
+
+    return ProjectSubmissionConfig(config_by_task_type=db_project.submission_config_by_task_type or {})
+
+
 # Project Thumbnail Management Endpoints
 
 @router.post("/{project_id}/thumbnail", status_code=status.HTTP_201_CREATED)