feat(infra): каркас проекта — uv, ruff, mypy, pytest, Docker Compose

- pyproject: Python 3.12, зависимости ADR-009, ruff/mypy strict/pytest/coverage
- app/: точка входа-заглушка с graceful shutdown по SIGTERM
- Dockerfile: multi-stage, uv, non-root (uid 10001), git+ssh для коммитов (#9);
  apt по HTTPS — в некоторых сетях обычный HTTP к deb.debian.org заблокирован
- docker-compose: bot + postgres 16, healthcheck, лимиты памяти, ротация логов
- Makefile: install/lint/fmt/test/cov/up/down/logs/ps; .env.example

Refs #3

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/main.py

@@ -0,0 +1,28 @@
+"""Entry point. For now a stub that idles until stopped; the bot itself lands in #4."""
+
+import asyncio
+import logging
+import signal
+
+from app import __version__
+
+log = logging.getLogger("tgit")
+
+
+async def run(stop: asyncio.Event) -> None:
+    log.info("tgit %s started", __version__)
+    await stop.wait()
+    log.info("tgit stopped")
+
+
+def main() -> None:
+    logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(name)s: %(message)s")
+
+    async def _main() -> None:
+        stop = asyncio.Event()
+        loop = asyncio.get_running_loop()
+        for sig in (signal.SIGINT, signal.SIGTERM):
+            loop.add_signal_handler(sig, stop.set)
+        await run(stop)
+
+    asyncio.run(_main())