feat: overhaul with modular API, agent endpoints, migrations, backup and tests

- Split monolithic app.py into server/api/ routers
- Add Pydantic schemas for input validation
- Add /agent/* API with separate AGENT_TOKEN auth
- Replace static schema.sql with versioned migrations (datenerhaltend)
- Add tools/backup_db.py for SQLite backups
- Add Dockerfile HEALTHCHECK and compose.yml AGENT_TOKEN env
- Add pytest tests for user and agent API
- Update README with API docs and deployment safety notes
- Bump version to 1.2.0

server/api/config.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from fastapi import APIRouter, Depends
+from fastapi.responses import JSONResponse
+
+from server.auth import require_auth
+from server.config_loader import load_meds_config, slot_to_dict
+from server.settings import settings
+
+router = APIRouter(prefix="/api/config", tags=["config"])
+
+NO_STORE = {"Cache-Control": "no-store"}
+
+
+@router.get("/")
+async def get_config(_: dict = Depends(require_auth)) -> JSONResponse:
+    config = load_meds_config()
+    return JSONResponse(
+        {
+            "timezone": str(config.timezone),
+            "slots": [slot_to_dict(s) for s in config.slots],
+            "version": settings.app_version,
+        },
+        headers=NO_STORE,
+    )