Add MiniMax LLM integration and local .env support

- Add .env to .gitignore (API keys stay local)
- Add LLM client with MiniMax and OpenAI support
- Update config to load from environment variables
- Wire up Architect agent to actually call the LLM
- Add MiniMax API key to local .env file

.gitignore

@@ -0,0 +1,31 @@
+# Dependencies
+__pycache__/
+*.egg-info/
+dist/
+build/
+.eggs/
+
+# Virtual environments
+venv/
+.venv/
+env/
+
+# Local environment
+.env
+.env.local
+*.local
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# Testing
+.pytest_cache/
+.coverage
+htmlcov/
+
+# Output
+output/
+*.log