Enhance Telegram bot with database integration and API features

- Added SQLite database support with Alembic for migrations.
- Implemented FastAPI for HTTP API to manage duties.
- Updated configuration to include database URL and HTTP port.
- Created entrypoint script for Docker to handle migrations and permissions.
- Expanded command handlers to register users and display duties.
- Developed a web application for calendar display of duties.
- Included necessary Pydantic schemas and SQLAlchemy models for data handling.
- Updated requirements.txt to include new dependencies for FastAPI and SQLAlchemy.

entrypoint.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+set -e
+# Ensure data dir exists and is writable by botuser (volume may be root-owned)
+mkdir -p /app/data
+chown botuser:botuser /app/data
+# Apply Alembic migrations (runs as root, creates DB in /app/data)
+alembic upgrade head
+# Ensure new DB file is owned by botuser so the app can write
+chown -R botuser:botuser /app/data
+# Run the app as botuser
+exec gosu botuser "$@"