Rewrite .cursorignore, .cursorrules, AGENTS.md for Muse v2

Replace AgentCeption-specific content with Muse-accurate rules: - .cursorignore: remove agentception/static refs, add dist/, .mypy_cache/ - .cursorrules: Muse stack, plugin architecture, verification commands, zero-tolerance typing rules, quick-reference table - AGENTS.md: full agent contract — architecture, branch discipline, layer rules, typing enforcement chain, verification checklist, scope of authority, anti-patterns