feat: glitchtip docker stack + local dev integration

WS-7 PR-1 — bring up self-hosted GlitchTip alongside the existing
dev stack. One compose file is portable to the production monitoring
host (RFC-WS-7 §3.1).

- docker-compose.glitchtip.yml: web/worker/postgres/redis pinned, web
  bound to 127.0.0.1:8200, internal network for postgres + valkey.
- docker/glitchtip/.env.example: documented dev defaults + production
  checklist; .env itself ignored.
- Makefile: services / services-stop merge both compose files; new
  services-glitchtip-status tail target.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -60,3 +60,7 @@ docs/.vitepress/cache
 
 # Claude Code runtime state
 .claude/*.lock
+
+# GlitchTip
+docker/glitchtip/.env
+backups/