chore: prepare 0.3.0

[JimmyDaddy]

Summary

• promote the validated 0.3.0-beta.1 package to 0.3.0
• update the changelog release heading and comparison link
• make no runtime or package-content changes beyond version metadata

Beta evidence

• Trusted Publisher release succeeded with SLSA provenance
• npm beta dist-tag points to 0.3.0-beta.1
• Vite and Expo Registry Consumer Canary passed
• Android API 24/31 and iOS Simulator runtime tests passed

Verification

• immutable Yarn install
• pre-commit ESLint and TypeScript checks
• commitlint
• npm pack dry run (58 files, 126 KB packed)