Add MIT license and model refresh plan

[udiedrichsen]

What changed

• add an MIT license for Idea Map project-authored source and documentation
• declare MIT in npm package metadata and explain the third-party/model-weight boundary in the README
• document an evidence-gated refresh path from qwen2.5:3b to qwen3.5:4b, with qwen3.5:9b as the fallback
• correct AGENTS.md and STATE.md to reflect the public GitHub remote without implying a deployment

Why

The public repository needs an explicit reusable source license. Model weights remain separate third-party artifacts: the current Qwen2.5 3B weights use the qwen-research license, while the proposed Qwen3.5 candidates use Apache 2.0. The runtime default stays unchanged until the new candidate matches the proven corpus and production-shaped performance gates.

Impact

This changes repository licensing and documentation only. It does not download a model, change the AI runtime, migrate data, publish an image, deploy to Cloudflare, or alter public behavior.

Validation

• npm run check — 24 files / 134 tests passed; TypeScript and production build passed
• npm run test:e2e — 42 passed; 2 intentional viewport-specific skips
• git diff --check — passed