Go Live: publish latest API docs (#171)

Publish the accumulated SkiaSharp / HarfBuzzSharp API documentation from main
to the live (published) branch. This is the first Go Live since #66 and rolls up
a large batch of docs automation, a full regeneration, and content/cross-reference
cleanup.

Highlights in this batch:

- Docs automation: automated API docs writer (#92, hardened in #155), daily
  update workflow, go-live workflow (#65), and a Learn Build status-based
  auto-merge gate (#82, #83) backed by check-learn-build.py and a
  .github/known-warnings.csv baseline.
- Regeneration: frameworks docs switched to latest-only monikers (#141), baseline
  reset to the Windows-generated output (#142), and stub regeneration moved to
  Linux via Mono (#147). This drops older, no-longer-shipping member/type pages
  (e.g. pre-v1.68 view APIs, the removed Android ISKRenderer interface, and the
  SKPaint text properties that moved to SKFont).
- Content: filled API documentation placeholders (#150, #151, #172) and fixed
  broken cross-references (#152).
- Cross-reference cleanup (#173): removed/repointed 36 obsolete xref-not-found
  references left behind by the latest-only-moniker regeneration — dangling links
  in 2019-era remarks to members that were since removed or relocated. Without
  this the Go Live build reported 160 warnings and the auto-merge gate (correctly)
  blocked the publish.

Build health at publish: 0 errors, 124 warnings, 0 suggestions. All 124 remaining
warnings are expected xref-not-found references to external framework types
(OpenTK, Gdk/Cairo/Graphene, ElmSharp/Tizen.NUI, Windows.UI.Xaml, Microsoft.UI.Xaml,
SharpVk, Vortice) that Learn cannot resolve and which are tracked in the
known-warnings.csv baseline — 0 new warnings versus baseline, so the gate passes.

Co-authored-by: Matthew Leibowitz <[email protected]>
Co-authored-by: Copilot App <[email protected]>

Go Live: publish latest API docs