feat: complete ChatGPT MCP phases 1-6 for Claude Code parity

Phase 1-2: instruction context with agent prompt, git/env, CLAUDE.md, skills, auto memory

Phase 3: global shell cwd persistence across ChatGPT MCP sessions

Phase 4: CHATGPT_TOOL_PROFILE=slim (23 tools, ~13KB tools/list)

Phase 5: post-edit hooks, remember, load_path_rules

Phase 6: Admin Project tab, init-claude-md, npm run test:all