refactor: migrate vendor auth, profile, team, dashboard, settings to modules

Tenancy module (identity & organizational hierarchy):
- vendor_auth.py: login, logout, /me endpoints
- vendor_profile.py: vendor profile get/update
- vendor_team.py: team management, roles, permissions, invitations

Core module (foundational non-domain features):
- vendor_dashboard.py: dashboard statistics
- vendor_settings.py: localization, business info, letzshop settings

All routes auto-discovered via is_self_contained=True.
Deleted 5 legacy files from app/api/v1/vendor/.

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

app/modules/tenancy/routes/api/__init__.py

@@ -2,10 +2,21 @@
 """
 Tenancy module API routes.
 
-Includes:
+Vendor routes:
 - /info/{vendor_code} - Public vendor info lookup
+- /auth/* - Vendor authentication (login, logout, /me)
+- /profile/* - Vendor profile management
+- /team/* - Team member management, roles, permissions
 """
 
 from .vendor import vendor_router
+from .vendor_auth import vendor_auth_router
+from .vendor_profile import vendor_profile_router
+from .vendor_team import vendor_team_router
 
-__all__ = ["vendor_router"]
+__all__ = [
+    "vendor_router",
+    "vendor_auth_router",
+    "vendor_profile_router",
+    "vendor_team_router",
+]