Prepare the v0.1.0 release

[veronicaz41]

Summary

• package install.sh and its checksum as immutable GitHub Release assets, and point README install/update commands at the latest release
• fail closed when the tag does not match BEAGLE_VERSION or npm publishing credentials are unavailable
• make npm publication rerunnable after partial success, generate GitHub release notes, and pin release/CI actions to commit SHAs
• include the MIT license in every npm package
• tighten README wire/telemetry and notification claims
• replace the stale AWS access-key-ID transcript with a real current beagle demo capture using AWS_SECRET_ACCESS_KEY

Validation

• bun run check
• all four release binaries cross-compile
• native release binary reports beagle 0.1.0
• all five npm tarballs pass npm pack --dry-run
• launcher tarball contains LICENSE, README, launcher, and package metadata
• packaged installer passes sh -n
• tag/version gate passes for v0.1.0
• release and CI workflow YAML parses cleanly
• live isolated demo/browser capture verified before replacing the README screenshot