refactor: migrate vendor APIs to token-based context and consolidate architecture

## Vendor-in-Token Architecture (Complete Migration)
- Migrate all vendor API endpoints from require_vendor_context() to token_vendor_id
- Update permission dependencies to extract vendor from JWT token
- Add vendor exceptions: VendorAccessDeniedException, VendorOwnerOnlyException,
  InsufficientVendorPermissionsException
- Shop endpoints retain require_vendor_context() for URL-based detection
- Add AUTH-004 architecture rule enforcing vendor context patterns
- Fix marketplace router missing /marketplace prefix

## Exception Pattern Fixes (API-003/API-004)
- Services raise domain exceptions, endpoints let them bubble up
- Add code_quality and content_page exception modules
- Move business logic from endpoints to services (admin, auth, content_page)
- Fix exception handling in admin, shop, and vendor endpoints

## Tailwind CSS Consolidation
- Consolidate CSS to per-area files (admin, vendor, shop, platform)
- Remove shared/cdn-fallback.html and shared/css/tailwind.min.css
- Update all templates to use area-specific Tailwind output files
- Remove Node.js config (package.json, postcss.config.js, tailwind.config.js)

## Documentation & Cleanup
- Update vendor-in-token-architecture.md with completed migration status
- Update architecture-rules.md with new rules
- Move migration docs to docs/development/migration/
- Remove duplicate/obsolete documentation files
- Merge pytest.ini settings into pyproject.toml

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

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

app/exceptions/vendor.py

@@ -148,3 +148,43 @@ class MaxVendorsReachedException(BusinessLogicException):
             error_code="MAX_VENDORS_REACHED",
             details=details,
         )
+
+
+class VendorAccessDeniedException(AuthorizationException):
+    """Raised when no vendor context is available for an authenticated endpoint."""
+
+    def __init__(self, message: str = "No vendor context available"):
+        super().__init__(
+            message=message,
+            error_code="VENDOR_ACCESS_DENIED",
+        )
+
+
+class VendorOwnerOnlyException(AuthorizationException):
+    """Raised when operation requires vendor owner role."""
+
+    def __init__(self, operation: str, vendor_code: str | None = None):
+        details = {"operation": operation}
+        if vendor_code:
+            details["vendor_code"] = vendor_code
+
+        super().__init__(
+            message=f"Operation '{operation}' requires vendor owner role",
+            error_code="VENDOR_OWNER_ONLY",
+            details=details,
+        )
+
+
+class InsufficientVendorPermissionsException(AuthorizationException):
+    """Raised when user lacks required vendor permission."""
+
+    def __init__(self, required_permission: str, vendor_code: str | None = None):
+        details = {"required_permission": required_permission}
+        if vendor_code:
+            details["vendor_code"] = vendor_code
+
+        super().__init__(
+            message=f"Permission required: {required_permission}",
+            error_code="INSUFFICIENT_VENDOR_PERMISSIONS",
+            details=details,
+        )