MAESTRO: add health endpoint

backend/app/schemas/health.py

@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from typing import Literal
+
+from pydantic import BaseModel, ConfigDict, Field
+
+
+class HealthResponse(BaseModel):
+    model_config = ConfigDict(populate_by_name=True)
+
+    status: Literal["up", "degraded", "down"]
+    version: str
+    uptime: float
+    scanner_count: int = Field(alias="scannerCount")
+
+
+__all__ = ["HealthResponse"]