Add backend and frontend skeleton

app/backend/features/health/schemas.py

@@ -0,0 +1,9 @@
+"""Pydantic schemas for health responses."""
+
+from pydantic import BaseModel, Field
+
+
+class HealthResponse(BaseModel):
+    status: str = Field(default="ok", description="Overall service status.")
+    service: str = Field(default="backend", description="Service name.")
+    environment: str = Field(default="development", description="Runtime environment.")