feat(api): add backend

routes and WebSockets

services/api/app/schemas/base.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+from typing import Generic, TypeVar
+from pydantic import BaseModel, Field
+
+T = TypeVar("T")
+
+
+class ApiError(BaseModel):
+    code: str = Field(..., examples=["validation_error", "db_error"])
+    message: str
+    details: dict | None = None
+
+
+class ApiResponse(BaseModel, Generic[T]):
+    success: bool = True
+    errors: list[ApiError] | None = None
+    count: int | None = None
+    data: T | None = None