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/content.py

@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+from fastapi import APIRouter, Depends
+from fastapi.responses import JSONResponse
+
+from server.ai import get_daily_motivation, get_roast_of_the_day
+from server.auth import require_auth
+from server.config_loader import load_meds_config
+from server.db import get_db
+
+router = APIRouter(prefix="/api", tags=["content"])
+
+NO_STORE = {"Cache-Control": "no-store"}
+
+
+@router.get("/roast")
+async def get_roast(_: dict = Depends(require_auth)) -> JSONResponse:
+    config = load_meds_config()
+    db = await get_db()
+    try:
+        data = await get_roast_of_the_day(db, config.timezone)
+    finally:
+        await db.close()
+    return JSONResponse(data, headers=NO_STORE)
+
+
+@router.get("/motivation")
+async def get_motivation(_: dict = Depends(require_auth)) -> JSONResponse:
+    config = load_meds_config()
+    db = await get_db()
+    try:
+        data = await get_daily_motivation(db, config.timezone)
+    finally:
+        await db.close()
+    return JSONResponse(data, headers=NO_STORE)