fix: runtime deployment fixes for Docker Compose stack

- Add .gitignore for __pycache__, node_modules, .playwright-mcp
- Add CLAUDE.md project instructions
- docker-compose: remove host port exposure for internal services,
  remove Ollama container (use host), add CORS origin, bake
  NEXT_PUBLIC_API_URL at build time, run alembic migrations on
  gateway startup, add CPU-only torch pre-install
- gateway: add CORS middleware, graceful Slack degradation without
  bot token, fix None guard on slack_handler
- gateway pyproject: add aiohttp dependency for slack-bolt async
- llm-pool pyproject: install litellm from GitHub (removed from PyPI),
  enable hatch direct references
- portal: enable standalone output in next.config.ts
- Remove orphaned migration 003_phase2_audit_kb.py (renamed to 004)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,31 @@
+# Python
+__pycache__/
+*.py[cod]
+*.egg-info/
+dist/
+build/
+.venv/
+*.egg
+
+# Node
+node_modules/
+.next/
+.turbo/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# Environment
+.env
+.env.local
+.env.production
+
+# Playwright
+.playwright-mcp/
+
+# OS
+.DS_Store
+Thumbs.db