chore: release v0.2.0-beta.2

[recrack]

Summary

• adopt Apache License 2.0 for project-owned source code and prose documentation beginning with v0.2.0-beta.2
• add NOTICE and a separate SideRefresh brand policy while preserving v0.2.0-beta.1 and earlier MIT terms
• package legal files in app and Headless builds and update active release, site, Product Hunt, and contribution documentation
• bump the app build to 3 and MCP server to 0.2.0-beta.2 for a source-only prerelease

Validation

• public-source validators and self-tests
• 10 Python tests
• 335 Swift tests
• sample and Headless/MCP validation
• Product Hunt asset, public site, homepage, and Pages publication validation
• app and Headless release builds, signatures, embedded legal files, app version, and MCP version
• canonical Apache-2.0 LICENSE comparison

No binary asset will be attached. Stable signed/notarized distribution remains gated.

Closes #20