docs: update authentication dependency names across documentation

Updated all documentation to use correct authentication dependency names:
- HTML pages: get_current_admin_from_cookie_or_header, get_current_vendor_from_cookie_or_header, get_current_customer_from_cookie_or_header
- API endpoints: get_current_admin_api, get_current_vendor_api, get_current_customer_api

Changes:
- Updated authentication flow diagrams with correct dependency names for admin and vendor flows
- Added comprehensive customer/shop authentication flow documentation
- Updated cookie isolation architecture to show all three contexts (admin, vendor, shop)
- Expanded security boundary enforcement diagram to include shop routes
- Added customer cross-context prevention examples
- Updated all code examples in frontend and backend documentation
- Fixed import statements to use app.api.deps instead of app.core.auth

Files updated:
- docs/api/authentication-flow-diagrams.md (added customer flows)
- docs/frontend/admin/page-templates.md
- docs/frontend/admin/architecture.md
- docs/frontend/shared/ui-components.md
- docs/frontend/shared/sidebar.md
- docs/development/exception-handling.md
- docs/architecture/diagrams/vendor-domain-diagrams.md
- docs/backend/admin-integration-guide.md
- docs/backend/admin-feature-integration.md

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

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

docs/frontend/admin/architecture.md

@@ -128,7 +128,7 @@ Example:
   @router.get("/admin/dashboard")
   async def admin_dashboard_page(
       request: Request,
-      current_user: User = Depends(get_current_admin_user)
+      current_user: User = Depends(get_current_admin_from_cookie_or_header)
   ):
       return templates.TemplateResponse(
           "admin/dashboard.html",
@@ -364,10 +364,12 @@ Windmill Dashboard Theme:
 Auth Flow:
   1. Login → POST /api/v1/admin/auth/login
   2. API → Verify credentials + check admin role
-  3. API → Return JWT token
-  4. JavaScript → Store in localStorage
-  5. API Client → Add to all requests
-  6. Routes → Verify with get_current_admin_user
+  3. API → Return JWT token + set admin_token cookie
+  4. JavaScript → Store in localStorage (optional)
+  5. HTML Pages → Use cookie (automatic)
+  6. API Calls → Use Authorization header
+  7. Routes → Verify with get_current_admin_from_cookie_or_header (HTML)
+            or get_current_admin_api (API endpoints)
 
 Protected Routes:
   • All /admin/* routes

docs/frontend/admin/page-templates.md

@@ -862,7 +862,7 @@ pageLog.info('[Page Name] module loaded');
 
 ```python
 from fastapi import APIRouter, Request, Depends
-from app.core.auth import get_current_admin_user
+from app.api.deps import get_current_admin_from_cookie_or_header
 from app.models.database.user import User
 
 router = APIRouter()
@@ -870,12 +870,12 @@ router = APIRouter()
 @router.get("/admin/[page-route]")
 async def [page_name]_page(
     request: Request,
-    current_user: User = Depends(get_current_admin_user)
+    current_user: User = Depends(get_current_admin_from_cookie_or_header)
 ):
     """
     [Page Name] page
     Displays [description]
-    
+
     Requires admin authentication.
     """
     return templates.TemplateResponse(