feat(runner): tgit-runner — сервисы в песочнице на хосте, деплой после push (#13)

- infra/runner/tgit-runner: deploy/restart/remove/list по SSH forced command;
  аргументы не исполняются и не глобятся; архив — только файлы и папки,
  без «..», ≤ 20 МБ, есть main.py; health_url — только localhost
- песочница: uid 10001, read-only, tmpfs noexec, cap-drop ALL,
  no-new-privileges, 128 МБ без swap, 0.25 CPU, 64 PID, --network none
  (сеть — только по egress-allow админа), лимит 10 сервисов, 2 образа
- новая версия стартует рядом (-next) и заменяет старую, только став
  healthy; иначе удаляется, старая работает, exit 3
- бот: после push git archive изменённых services/<name>/ → runner;
  автору — «🚀 работает» или «⛔ не развёрнут» с логом, команде — алерт ⛔;
  удалённая папка → remove; «♻️ Перезапустить» в «Статусе» для админа (S-5)
- examples/escape_attempts: все попытки выбраться — BLOCKED на живом Docker
- install.sh, authorized_keys.example; CD бота обновляет runner на хосте

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

app/runner/client.py

@@ -0,0 +1,85 @@
+"""SSH to `tgit-runner`: the key can run nothing else (forced command), so the «command» is just its arguments."""
+
+import asyncio
+import base64
+import logging
+import os
+import re
+import tempfile
+from dataclasses import dataclass
+from pathlib import Path
+
+from app.config import RunnerSettings
+
+log = logging.getLogger(__name__)
+
+SERVICE = re.compile(r"^[a-z][a-z0-9-]{1,30}$")  # the runner checks the same — refuse early, with a clear reason
+SHA = re.compile(r"^[0-9a-f]{7,40}$")
+
+
+@dataclass(frozen=True)
+class RunnerResult:
+    ok: bool
+    code: int  # 0 ok · 2 bad request · 3 not healthy · 4 limit · 5 build failed · 255 ssh · -1 timeout
+    summary: str  # the runner's last line without OK/FAIL
+    output: str  # everything, for logs and the user's log tail
+
+    @property
+    def tail(self) -> str:
+        lines = self.output.strip().splitlines()[:-1]
+        return "\n".join(lines[-20:])
+
+
+class RunnerClient:
+    def __init__(self, settings: RunnerSettings) -> None:
+        self._s = settings
+        self._key = self._materialize_key()
+
+    def _materialize_key(self) -> Path | None:
+        if self._s.ssh_key_b64 is None:
+            return None
+        key = base64.b64decode(self._s.ssh_key_b64.get_secret_value())
+        fd, name = tempfile.mkstemp(prefix="tgit-runner-")
+        with os.fdopen(fd, "wb") as f:
+            f.write(key if key.endswith(b"\n") else key + b"\n")
+        return Path(name)
+
+    def _ssh(self) -> list[str]:
+        cmd = ["ssh", "-F", "/dev/null", "-p", str(self._s.port), "-o", "BatchMode=yes", "-o", "ConnectTimeout=20"]
+        cmd += ["-o", "StrictHostKeyChecking=accept-new", "-o", f"UserKnownHostsFile={tempfile.gettempdir()}/tgit-kh"]
+        if self._key is not None:
+            cmd += ["-i", str(self._key), "-o", "IdentitiesOnly=yes"]
+        return [*cmd, f"{self._s.user}@{self._s.host}"]
+
+    async def run(self, *args: str, stdin: bytes = b"") -> RunnerResult:
+        proc = await asyncio.create_subprocess_exec(
+            *self._ssh(),
+            *args,
+            stdin=asyncio.subprocess.PIPE,
+            stdout=asyncio.subprocess.PIPE,
+            stderr=asyncio.subprocess.STDOUT,
+        )
+        try:
+            out, _ = await asyncio.wait_for(proc.communicate(stdin), timeout=self._s.timeout)
+        except TimeoutError:
+            proc.kill()
+            await proc.wait()
+            return RunnerResult(False, -1, "timeout", "")
+        text = out.decode(errors="replace")
+        last = text.strip().splitlines()[-1] if text.strip() else ""
+        code = proc.returncode if proc.returncode is not None else -1
+        ok = code == 0 and last.startswith("OK")
+        summary = last.removeprefix("OK ").removeprefix("FAIL ") if last.startswith(("OK", "FAIL")) else last[:200]
+        if not ok:
+            log.warning("runner %s: exit %s: %s", args[0] if args else "", code, summary)
+        return RunnerResult(ok, code, summary, text)
+
+    async def deploy(self, service: str, sha: str, archive: bytes) -> RunnerResult:
+        if not SERVICE.match(service) or not SHA.match(sha):
+            return RunnerResult(False, 2, "bad service name or sha", "")
+        return await self.run("deploy", service, sha, stdin=archive)
+
+    async def restart(self, service: str) -> RunnerResult:
+        if not SERVICE.match(service):
+            return RunnerResult(False, 2, "bad service name", "")
+        return await self.run("restart", service)