refactor: migrate templates and static files to self-contained modules

Templates Migration:
- Migrate admin templates to modules (tenancy, billing, monitoring, marketplace, etc.)
- Migrate vendor templates to modules (tenancy, billing, orders, messaging, etc.)
- Migrate storefront templates to modules (catalog, customers, orders, cart, checkout, cms)
- Migrate public templates to modules (billing, marketplace, cms)
- Keep shared templates in app/templates/ (base.html, errors/, partials/, macros/)
- Migrate letzshop partials to marketplace module

Static Files Migration:
- Migrate admin JS to modules: tenancy (23 files), core (5 files), monitoring (1 file)
- Migrate vendor JS to modules: tenancy (4 files), core (2 files)
- Migrate shared JS: vendor-selector.js to core, media-picker.js to cms
- Migrate storefront JS: storefront-layout.js to core
- Keep framework JS in static/ (api-client, utils, money, icons, log-config, lib/)
- Update all template references to use module_static paths

Naming Consistency:
- Rename static/platform/ to static/public/
- Rename app/templates/platform/ to app/templates/public/
- Update all extends and static references

Documentation:
- Update module-system.md with shared templates documentation
- Update frontend-structure.md with new module JS organization

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

tests/unit/services/test_onboarding_service.py

@@ -15,7 +15,7 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 
-from app.services.onboarding_service import OnboardingService
+from app.modules.marketplace.services.onboarding_service import OnboardingService
 from app.modules.marketplace.models import OnboardingStatus, OnboardingStep, VendorOnboarding
 
 
@@ -50,7 +50,7 @@ class TestOnboardingServiceCRUD:
 
     def test_get_onboarding_or_raise_raises_exception(self, db):
         """Test get_onboarding_or_raise raises OnboardingNotFoundException"""
-        from app.exceptions import OnboardingNotFoundException
+        from app.modules.marketplace.exceptions import OnboardingNotFoundException
 
         service = OnboardingService(db)
         with pytest.raises(OnboardingNotFoundException):
@@ -214,7 +214,7 @@ class TestOnboardingServiceStep1:
 
     def test_complete_company_profile_raises_for_missing_vendor(self, db):
         """Test complete_company_profile raises for non-existent vendor"""
-        from app.exceptions import VendorNotFoundException
+        from app.modules.tenancy.exceptions import VendorNotFoundException
 
         service = OnboardingService(db)
 
@@ -238,7 +238,7 @@ class TestOnboardingServiceStep2:
     def test_test_letzshop_api_returns_result(self, db, test_vendor):
         """Test test_letzshop_api returns connection test result"""
         with patch(
-            "app.services.onboarding_service.LetzshopCredentialsService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopCredentialsService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_instance.test_api_key.return_value = (True, 150.0, None)
@@ -256,7 +256,7 @@ class TestOnboardingServiceStep2:
     def test_test_letzshop_api_returns_error(self, db, test_vendor):
         """Test test_letzshop_api returns error on failure"""
         with patch(
-            "app.services.onboarding_service.LetzshopCredentialsService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopCredentialsService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_instance.test_api_key.return_value = (False, None, "Invalid API key")
@@ -273,7 +273,7 @@ class TestOnboardingServiceStep2:
 
     def test_complete_letzshop_api_requires_step1(self, db, test_vendor):
         """Test complete_letzshop_api requires step 1 complete"""
-        from app.exceptions import OnboardingStepOrderException
+        from app.modules.marketplace.exceptions import OnboardingStepOrderException
 
         # Create onboarding with step 1 not complete
         onboarding = VendorOnboarding(
@@ -319,7 +319,7 @@ class TestOnboardingServiceStep3:
 
     def test_complete_product_import_requires_csv_url(self, db, test_vendor):
         """Test complete_product_import requires at least one CSV URL"""
-        from app.exceptions import OnboardingCsvUrlRequiredException
+        from app.modules.marketplace.exceptions import OnboardingCsvUrlRequiredException
 
         # Create onboarding with steps 1 and 2 complete
         onboarding = VendorOnboarding(
@@ -391,7 +391,7 @@ class TestOnboardingServiceStep4:
         db.commit()
 
         with patch(
-            "app.services.onboarding_service.LetzshopOrderService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopOrderService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_instance.get_running_historical_import_job.return_value = None
@@ -425,7 +425,7 @@ class TestOnboardingServiceStep4:
         db.commit()
 
         with patch(
-            "app.services.onboarding_service.LetzshopOrderService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopOrderService"
         ) as mock_service:
             mock_instance = MagicMock()
             existing_job = MagicMock()
@@ -446,7 +446,7 @@ class TestOnboardingServiceStep4:
     def test_get_order_sync_progress_not_found(self, db, test_vendor):
         """Test get_order_sync_progress for non-existent job"""
         with patch(
-            "app.services.onboarding_service.LetzshopOrderService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopOrderService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_instance.get_historical_import_job_by_id.return_value = None
@@ -464,7 +464,7 @@ class TestOnboardingServiceStep4:
     def test_get_order_sync_progress_completed(self, db, test_vendor):
         """Test get_order_sync_progress for completed job"""
         with patch(
-            "app.services.onboarding_service.LetzshopOrderService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopOrderService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_job = MagicMock()
@@ -494,7 +494,7 @@ class TestOnboardingServiceStep4:
     def test_get_order_sync_progress_processing(self, db, test_vendor):
         """Test get_order_sync_progress for processing job"""
         with patch(
-            "app.services.onboarding_service.LetzshopOrderService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopOrderService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_job = MagicMock()
@@ -525,7 +525,7 @@ class TestOnboardingServiceStep4:
 
     def test_complete_order_sync_raises_for_missing_job(self, db, test_vendor):
         """Test complete_order_sync raises for non-existent job"""
-        from app.exceptions import OnboardingSyncJobNotFoundException
+        from app.modules.marketplace.exceptions import OnboardingSyncJobNotFoundException
 
         onboarding = VendorOnboarding(
             vendor_id=test_vendor.id,
@@ -535,7 +535,7 @@ class TestOnboardingServiceStep4:
         db.commit()
 
         with patch(
-            "app.services.onboarding_service.LetzshopOrderService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopOrderService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_instance.get_historical_import_job_by_id.return_value = None
@@ -550,7 +550,7 @@ class TestOnboardingServiceStep4:
 
     def test_complete_order_sync_raises_if_not_complete(self, db, test_vendor):
         """Test complete_order_sync raises if job still running"""
-        from app.exceptions import OnboardingSyncNotCompleteException
+        from app.modules.marketplace.exceptions import OnboardingSyncNotCompleteException
 
         onboarding = VendorOnboarding(
             vendor_id=test_vendor.id,
@@ -560,7 +560,7 @@ class TestOnboardingServiceStep4:
         db.commit()
 
         with patch(
-            "app.services.onboarding_service.LetzshopOrderService"
+            "app.modules.marketplace.services.onboarding_service.LetzshopOrderService"
         ) as mock_service:
             mock_instance = MagicMock()
             mock_job = MagicMock()