feat: Phase 2.7+3 — full integration, config update, systemd unit

- Wire all goroutines in main.go: watcher, quota monitor, account
  switcher, dispatcher, janitor, and 10s state flush loop
- Add missing sections to config.example.yaml: notifications,
  dispatcher, watcher, janitor
- Add scripts/claude-failover.service systemd unit

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

config.example.yaml

@@ -82,3 +82,35 @@ mcp_http:
   bearer_token_env: CLAUDE_FAILOVER_BEARER
   # Paths exposed (all read-only except explicitly listed mutating routes).
   enable_trigger: true     # allow /trigger/dispatch, /trigger/swap
+
+# ---------------------------------------------------------------------------
+# notifications
+# ---------------------------------------------------------------------------
+notifications:
+  telegram_token_env: TELEGRAM_BOT_TOKEN
+  telegram_chat_id_env: TELEGRAM_CHAT_ID
+  resend_api_key_env: RESEND_API_KEY
+  notify_email_env: CLAUDE_FAILOVER_NOTIFY_EMAIL
+
+# ---------------------------------------------------------------------------
+# dispatcher
+# ---------------------------------------------------------------------------
+dispatcher:
+  projects_dir: /home/ubuntu/projects
+  idle_timeout: 60m
+  prompt_timeout: 30s
+  max_dispatch_per_task: 3
+
+# ---------------------------------------------------------------------------
+# watcher
+# ---------------------------------------------------------------------------
+watcher:
+  interval: 30s
+  done_signal_dir: /tmp
+  idle_timeout: 60m
+
+# ---------------------------------------------------------------------------
+# janitor
+# ---------------------------------------------------------------------------
+janitor:
+  interval: 5m