refactor: migrate messaging and media routes to modules

Messaging module (communication):
- vendor_messages.py: Conversation and message management
- vendor_notifications.py: Vendor notifications
- vendor_email_settings.py: SMTP and provider configuration
- vendor_email_templates.py: Email template customization

CMS module (content management):
- vendor_media.py: Media library management
- vendor_content_pages.py: Content page overrides

All routes auto-discovered via is_self_contained=True.
Deleted 5 legacy files from app/api/v1/vendor/.
app/api/v1/vendor/ now empty except for __init__.py (auto-discovery only).

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

app/api/v1/vendor/__init__.py

@@ -21,44 +21,23 @@ Self-contained modules (auto-discovered from app/modules/{module}/routes/api/ven
 - orders: Order management, fulfillment, exceptions, invoices
 - marketplace: Letzshop integration, product sync, onboarding
 - catalog: Vendor product catalog management
-- cms: Content pages management
+- cms: Content pages management, media library
 - customers: Customer management
 - payments: Payment configuration, Stripe connect, transactions
 - tenancy: Vendor info, auth, profile, team management
+- messaging: Messages, notifications, email settings, email templates
+- core: Dashboard, settings
 """
 
 from fastapi import APIRouter
 
-# Import all sub-routers (legacy routes that haven't been migrated to modules)
-from . import (
-    email_settings,
-    email_templates,
-    media,
-    messages,
-    notifications,
-)
-
 # Create vendor router
 router = APIRouter()
 
 # ============================================================================
 # JSON API ROUTES ONLY
 # ============================================================================
-# These routes return JSON and are mounted at /api/v1/vendor/*
-
-# Email configuration
-router.include_router(email_templates.router, tags=["vendor-email-templates"])
-router.include_router(email_settings.router, tags=["vendor-email-settings"])
-
-# Services (with prefixes: /media/*, etc.)
-router.include_router(media.router, tags=["vendor-media"])
-router.include_router(notifications.router, tags=["vendor-notifications"])
-router.include_router(messages.router, tags=["vendor-messages"])
-
-# Services (with prefixes: /media/*, etc.)
-router.include_router(media.router, tags=["vendor-media"])
-router.include_router(notifications.router, tags=["vendor-notifications"])
-router.include_router(messages.router, tags=["vendor-messages"])
+# All vendor routes are now auto-discovered from self-contained modules.
 
 
 # ============================================================================