v0.3.0: web GUI, menu CLI, 13 features

Local web GUI (Overview, Agents, real-terminal Commands with menu+shell PTY modes, Memory, Skills, Project, Activity, Settings with 19 themes, About, Update modal). Menu-only interactive CLI. 13 new subcommand features. haveBin PATH scan, update-info caching. Install hints moved to theelephantcoder.com/agent-harness. M6 local-model evidence in docs/benchmarks.md. Full sweep green: tsc, eslint, 27 vitest, 20 pytest, 3h soak zero failures.