pikuri 0.0.1

A library for assembling AI assistants: Pikuri::Agent (a thin wrapper around ruby_llm's chat loop), Pikuri::Tool with strict argument validation, a listener surface for rendering / budgets / sub-agents, and a small set of bundled tools (calculator, web search, web scrape, fetch, plus six coding tools: read / write / edit / grep / glob / bash). Downstream projects (notably the planned pikuri-tui) wire these into actual binaries. The repo also ships `bin/pikuri-chat` and `bin/pikuri-code` as demo entry points, but they are NOT installed by `gem install pikuri` — they exist to show how to wire the library together and to support development.