Studio instructions

Studio ships on macOS, and the install page says it does not

The page opened with "Alpha channel, Windows only" and told readers that only
Windows builds are available and that macOS would follow. The macOS half is
false. Verified against the artifacts rather than taken on report:

  200  release/alpha/DCS.latest.msi
  200  release/alpha/DCS.latest.dmg     <- ships today
  404  beta, both platforms
  404  stable, both platforms

So Studio is alpha-only, which the warning got right, and it is alpha on BOTH
platforms, which it got wrong. The download section offered only the .msi, so a
Mac reader landed on our own install page, read that their platform was not
supported, and left. The build was one link away the whole time.

The warning now says alpha-only across both platforms, the dmg has a download
button, and there is a macOS section.

The macOS steps are sourced, not adapted from the 3D page on the assumption
that the two are alike. The bundle name is DCS.app, read off the dmg pipeline
(IF.APM.App.Avalonia/pipelines/cd-dmg.yml, sourceAppBundleName, with its own
comment recording that Dotnet.Bundle produces it from CFBundleName). The
quarantine removal is the same step 3D's macOS page documents, because it is a
property of unsigned bundles rather than of that product.

Deliberately not copied from 3D: its ring language. 3D is macOS alpha only with
Windows on all three rings, Studio is alpha only on both, and both are correct
for their own product (Friday, bus #2183, founder-confirmed). Nothing here
implies Studio will follow 3D's shape.

Raised by Friday on bus #2182 as the one part of that ask that was not low
priority. The structure mirror in the rest of it is not in this change.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>