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

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "takeyourmeds"
-version = "1.1.0"
-description = "Medikamenten-PWA mit Push-Erinnerungen und sarkastischem Humor"
+version = "1.2.0"
+description = "Medikamenten-PWA mit Push-Erinnerungen, Agent-API und sarkastischem Humor"
 requires-python = ">=3.11"
 dependencies = [
   "fastapi>=0.115",
@@ -16,6 +16,13 @@ dependencies = [
   "apscheduler>=3.10",
 ]
 
+[project.optional-dependencies]
+test = [
+  "pytest>=8.0",
+  "pytest-asyncio>=0.23",
+  "httpx>=0.27",
+]
+
 [build-system]
 requires = ["setuptools>=70", "wheel"]
 build-backend = "setuptools.build_meta"