clean: remove non-course files, add .gitignore for course-only repo

.gitignore

@@ -0,0 +1,63 @@
+# Course-only repo — no agent configs, research projects, or experiments
+.fusion/
+.pi/
+agentic-finance-review/
+bash-damage-from-within/
+bowser/
+brand-monitor/
+ceo-agents/
+claude-code-damage-control/
+claude-code-hooks-mastery/
+claude-code-is-programmable/
+exeuntu/
+extensions/
+just-prompt/
+lead-agents/
+mentor-disler/
+multica/
+nano-agent/
+paperclip/
+Plans/
+quick-data-mcp/
+single-file-agents/
+tac-agentic-engineer/
+tac-agentic-horizon/
+the-verifier-agent/
+the-verifier-agent-old/
+the-verifier-agent-system/
+ui-agents/
+ui-agents-broken/
+url-shortener/
+
+# Generated files
+node_modules/
+__pycache__/
+*.pyc
+.env
+*.log
+askpass.ps1
+backup_volumes.py
+backup_volumes.sh
+deploy_proxy.py
+development_log.md
+docker-compose.factory.yml
+factory_discovery.mjs
+generate_compose.py
+hello-world
+mythos-learnings.md
+nul
+pytest_validator.py
+session_test_log.md
+start-all.sh
+test_suite.py
+validator_test.py
+video-analysis-indydevdan-ui-agents.md
+
+# Site dependencies
+site/node_modules/
+site/.vitepress/cache/
+site/.vitepress/dist/
+
+# OS
+.DS_Store
+Thumbs.db