feat: project skeleton

- infra (k8s, kind, helm, docker) backbone is implemented
- security: implementation + unit tests are done

app/core/exceptions.py

@@ -0,0 +1,59 @@
+"""Custom HTTP exceptions for the API."""
+
+from fastapi import HTTPException, status
+
+
+class NotFoundError(HTTPException):
+    """Resource not found."""
+
+    def __init__(self, detail: str = "Resource not found") -> None:
+        super().__init__(status_code=status.HTTP_404_NOT_FOUND, detail=detail)
+
+
+class ConflictError(HTTPException):
+    """Conflict with current state (e.g., version mismatch)."""
+
+    def __init__(self, detail: str = "Conflict with current state") -> None:
+        super().__init__(status_code=status.HTTP_409_CONFLICT, detail=detail)
+
+
+class UnauthorizedError(HTTPException):
+    """Authentication required or failed."""
+
+    def __init__(self, detail: str = "Not authenticated") -> None:
+        super().__init__(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail=detail,
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+
+class ForbiddenError(HTTPException):
+    """Insufficient permissions."""
+
+    def __init__(self, detail: str = "Insufficient permissions") -> None:
+        super().__init__(status_code=status.HTTP_403_FORBIDDEN, detail=detail)
+
+
+class BadRequestError(HTTPException):
+    """Invalid request data."""
+
+    def __init__(self, detail: str = "Invalid request") -> None:
+        super().__init__(status_code=status.HTTP_400_BAD_REQUEST, detail=detail)
+
+
+class ValidationError(HTTPException):
+    """Validation failed."""
+
+    def __init__(self, detail: str = "Validation failed") -> None:
+        super().__init__(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail=detail)
+
+
+__all__ = [
+    "BadRequestError",
+    "ConflictError",
+    "ForbiddenError",
+    "NotFoundError",
+    "UnauthorizedError",
+    "ValidationError",
+]