[obselate]

Changes

• Collect the Changelog line from Build Goo with G# SDK 0.5.26 #176 in a separate commit. The v0.7.38-to-main log contains no other PRs.
• Synchronize release references to 0.7.39 and move the notes to 2026-10-19. Leave Unreleased empty.
• This release uses G# SDK 0.5.26 from merged Build Goo with G# SDK 0.5.26 #176.
• Regenerate 15 API pages and refresh the 29-file plugin reference mirror.

Verification

• Branch includes current origin/main. Posting account is obselate.
• release_version.py --check passes and --notes prints the 0.7.39 entry.
• Onboarding and accessibility package validation pass.
• Locally packed Goo, Goo.Accessibility, Goo.DevTools, Goo.DevTools.App and Goo.Templates 0.7.39.
• Fresh isolated template installation from the packed template uses Gsharp.NET.Sdk 0.5.26 and builds against locally packed Goo with zero warnings and errors.
• API generator build passes with zero warnings and errors. Whitespace check passes.
• Android packaging and consumer checks are CI-only.
• Builds ran sequentially with nice -n 19, ionice -c3, -m:1 and disabled MSBuild/shared compilation servers. No NativeAOT build was run.

Do not merge or tag automatically. The integrator tags after merge.