fix: add background task to onboarding order sync + migrate to GitLab

Onboarding fixes:
- Add missing background task trigger for order sync (step 4)
- Import process_historical_import task in onboarding API

GitLab migration:
- Update audit rules to support both GitHub and GitLab paths
- Add .gitlab-ci.yml with lint, test, security, build stages
- Add merge request template (.gitlab/merge_request_templates/default.md)
- Update validate_audit.py to check for GitLab equivalents

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/api/v1/vendor/onboarding.py

@@ -13,12 +13,13 @@ Vendor Context: Uses token_vendor_id from JWT token (authenticated vendor API pa
 
 import logging
 
-from fastapi import APIRouter, Depends
+from fastapi import APIRouter, BackgroundTasks, Depends
 from sqlalchemy.orm import Session
 
 from app.api.deps import get_current_vendor_api
 from app.core.database import get_db
 from app.services.onboarding_service import OnboardingService
+from app.tasks.letzshop_tasks import process_historical_import
 from models.database.user import User
 from models.schema.onboarding import (
     CompanyProfileRequest,
@@ -206,6 +207,7 @@ def save_product_import_config(
 @router.post("/step/order-sync/trigger", response_model=OrderSyncTriggerResponse)
 def trigger_order_sync(
     request: OrderSyncTriggerRequest,
+    background_tasks: BackgroundTasks,
     current_user: User = Depends(get_current_vendor_api),
     db: Session = Depends(get_db),
 ):
@@ -222,6 +224,16 @@ def trigger_order_sync(
         include_products=request.include_products,
     )
     db.commit()  # Commit at API level for transaction control
+
+    # Queue background task to process the import
+    if result.get("success") and result.get("job_id"):
+        background_tasks.add_task(
+            process_historical_import,
+            result["job_id"],
+            current_user.token_vendor_id,
+        )
+        logger.info(f"Queued historical import task for job {result['job_id']}")
+
     return result