docs: prepare v0.2.0 release metadata

[amirbrooks]

Summary

• publish package discovery, changelog, documentation, and security metadata
• record the current verified v0.2.0 source/CI preparation state without claiming a public binary release
• document the official universal2 Python and secure notarization-profile prerequisites for future release operators

Validation

• built-in Codex review: clean
• Ruff lint and format: clean
• 257 Python tests with ResourceWarning promoted to errors
• Python build/install, exact hash-lock dependency check, all CLI help screens
• 112 Swift tests in debug and release configurations, optimized Swift build
• complete local macOS app build, signatures, Hardened Runtime, sandbox entitlements, architecture, privacy scan, native license map, helper protocol smoke, and 19-page PDF raster check
• source-bound wheel/sdist built and verified against commit b1886df and tree 0bb872b2a91973e1a366bfd920650cf3ca4c4f78

This PR intentionally does not create a tag, claim notarization, or publish v0.2.0 assets. Those remain gated by the configured notary profile and clean-device acceptance contract.