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/code_quality.py

@@ -0,0 +1,95 @@
+# app/exceptions/code_quality.py
+"""
+Code Quality Domain Exceptions
+
+These exceptions are raised by the code quality service layer
+and converted to HTTP responses by the global exception handler.
+"""
+
+from app.exceptions.base import (
+    BusinessLogicException,
+    ExternalServiceException,
+    ResourceNotFoundException,
+    ValidationException,
+)
+
+
+class ViolationNotFoundException(ResourceNotFoundException):
+    """Raised when a violation is not found."""
+
+    def __init__(self, violation_id: int):
+        super().__init__(
+            resource_type="Violation",
+            identifier=str(violation_id),
+            error_code="VIOLATION_NOT_FOUND",
+        )
+
+
+class ScanNotFoundException(ResourceNotFoundException):
+    """Raised when a scan is not found."""
+
+    def __init__(self, scan_id: int):
+        super().__init__(
+            resource_type="Scan",
+            identifier=str(scan_id),
+            error_code="SCAN_NOT_FOUND",
+        )
+
+
+class ScanExecutionException(ExternalServiceException):
+    """Raised when architecture scan execution fails."""
+
+    def __init__(self, reason: str):
+        super().__init__(
+            service_name="ArchitectureValidator",
+            message=f"Scan execution failed: {reason}",
+            error_code="SCAN_EXECUTION_FAILED",
+        )
+
+
+class ScanTimeoutException(ExternalServiceException):
+    """Raised when architecture scan times out."""
+
+    def __init__(self, timeout_seconds: int = 300):
+        super().__init__(
+            service_name="ArchitectureValidator",
+            message=f"Scan timed out after {timeout_seconds} seconds",
+            error_code="SCAN_TIMEOUT",
+        )
+
+
+class ScanParseException(BusinessLogicException):
+    """Raised when scan results cannot be parsed."""
+
+    def __init__(self, reason: str):
+        super().__init__(
+            message=f"Failed to parse scan results: {reason}",
+            error_code="SCAN_PARSE_FAILED",
+        )
+
+
+class ViolationOperationException(BusinessLogicException):
+    """Raised when a violation operation fails."""
+
+    def __init__(self, operation: str, violation_id: int, reason: str):
+        super().__init__(
+            message=f"Failed to {operation} violation {violation_id}: {reason}",
+            error_code="VIOLATION_OPERATION_FAILED",
+            details={
+                "operation": operation,
+                "violation_id": violation_id,
+                "reason": reason,
+            },
+        )
+
+
+class InvalidViolationStatusException(ValidationException):
+    """Raised when a violation status transition is invalid."""
+
+    def __init__(self, violation_id: int, current_status: str, target_status: str):
+        super().__init__(
+            message=f"Cannot change violation {violation_id} from '{current_status}' to '{target_status}'",
+            field="status",
+            value=target_status,
+        )
+        self.error_code = "INVALID_VIOLATION_STATUS"