release: prepare Proofing Gallery 0.10.0

[soerennb]

Summary

• publish the sanitized public history for the 0.10.0 release
• move the user-facing changelog entry from Unreleased to 0.10.0
• include the reviewed dependency and workflow lockfile state

Verification

• two independent sanitizer runs produced the same commit
• gitleaks history scans passed for both runs
• no internal Beads/agent metadata is present
• local lint, tests, build, package, upgrade, compatibility, and E2E gates passed on the internal source

The branch was generated by the reviewed incremental public-history sanitizer from internal main; no internal history or metadata is being pushed.