docs: README по требованиям к оформлению и демо-сервисы examples/ (#19)

- README: цели и задачи, что реализовано, развёртывание (локально за 5 минут
  и полный стек), переменные, команды и данные, используемые API,
  ограничения и лимиты, что не сделано, структура репозитория
- examples/: hello (healthy + материал для grep/агента), crash (💥 и 🔁),
  cpu_hog (🔥), unhealthy (🩺), syntax_error/lint_fail для коммита,
  вопросы агенту и атаки; make demo-up / demo-down в том же Compose-проекте
- make local-proxy: read-only Docker API для `make run`
- ARCHITECTURE: краш при restart-политике и гистерезис алертов

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

examples/docker-compose.yml

@@ -0,0 +1,55 @@
+# Demo services next to the bot — the same Compose project, so the bot sees them on its network:
+#   make demo-up    (= docker compose -f docker-compose.yml -f examples/docker-compose.yml up -d)
+#   make demo-down
+# The label tgit.managed=true is what makes them appear in «🩺 Статус», «📜 Логи» and alerts.
+x-demo: &demo
+  image: python:3.12-slim
+  working_dir: /demo
+  volumes:
+    - ./examples:/demo:ro
+  environment:
+    PYTHONUNBUFFERED: "1"
+  mem_limit: 64m
+  logging:
+    options: { max-size: "5m", max-file: "2" }
+
+services:
+  demo-hello:
+    <<: *demo
+    command: ["python", "hello_service.py"]
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:8000/health')"]
+      interval: 10s
+      timeout: 3s
+      retries: 3
+    labels:
+      tgit.managed: "true"
+      tgit.health_url: http://demo-hello:8000/health
+
+  demo-crash:
+    <<: *demo
+    command: ["python", "crash.py"]
+    restart: on-failure
+    labels:
+      tgit.managed: "true"
+
+  demo-cpu-hog:
+    <<: *demo
+    command: ["python", "cpu_hog.py"]
+    restart: unless-stopped
+    cpus: 1.0
+    labels:
+      tgit.managed: "true"
+
+  demo-unhealthy:
+    <<: *demo
+    command: ["python", "unhealthy.py"]
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "false"]
+      interval: 10s
+      retries: 2
+      start_period: 5s
+    labels:
+      tgit.managed: "true"