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_message_attachment_service.py

@@ -10,7 +10,7 @@ from unittest.mock import AsyncMock, MagicMock, patch
 import pytest
 from fastapi import UploadFile
 
-from app.services.message_attachment_service import (
+from app.modules.messaging.services.message_attachment_service import (
     ALLOWED_MIME_TYPES,
     DEFAULT_MAX_FILE_SIZE_MB,
     IMAGE_MIME_TYPES,
@@ -101,7 +101,7 @@ class TestMessageAttachmentServiceMaxFileSize:
     def test_get_max_file_size_from_settings(self, db, attachment_service):
         """Test retrieving max file size from platform settings."""
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = 15
             max_size = attachment_service.get_max_file_size_bytes(db)
@@ -110,7 +110,7 @@ class TestMessageAttachmentServiceMaxFileSize:
     def test_get_max_file_size_default(self, db, attachment_service):
         """Test default max file size when setting not found."""
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = DEFAULT_MAX_FILE_SIZE_MB
             max_size = attachment_service.get_max_file_size_bytes(db)
@@ -119,7 +119,7 @@ class TestMessageAttachmentServiceMaxFileSize:
     def test_get_max_file_size_invalid_value(self, db, attachment_service):
         """Test handling of invalid setting value."""
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = "invalid"
             max_size = attachment_service.get_max_file_size_bytes(db)
@@ -142,7 +142,7 @@ class TestMessageAttachmentServiceValidateAndStore:
         )
 
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = 10
 
@@ -181,7 +181,7 @@ class TestMessageAttachmentServiceValidateAndStore:
         )
 
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = 10
 
@@ -208,7 +208,7 @@ class TestMessageAttachmentServiceValidateAndStore:
         )
 
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = 10
 
@@ -233,7 +233,7 @@ class TestMessageAttachmentServiceValidateAndStore:
         )
 
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = 10  # 10 MB limit
 
@@ -257,7 +257,7 @@ class TestMessageAttachmentServiceValidateAndStore:
         file.filename = None  # Ensure it's None
 
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = 10
 
@@ -282,7 +282,7 @@ class TestMessageAttachmentServiceValidateAndStore:
         file.content_type = None
 
         with patch(
-            "app.services.message_attachment_service.admin_settings_service"
+            "app.modules.messaging.services.message_attachment_service.admin_settings_service"
         ) as mock_settings:
             mock_settings.get_setting_value.return_value = 10