feat(desktop): open What's new in beta from the command palette and Settings - #57940

Issue for this PR

N/A. Follows #57886. Kit asked for a way back to the beta changelog after its dialog closes: a ⌘K command or setting, and a full page.

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

"What's new in beta" can now be opened from anywhere on beta builds and the desktop dev server:

• ⌘K: a "What's new in beta" command (it also matches "changelog" and "release notes") opens the page.
• Settings: a "What's new in beta" page in the Settings nav (and in Settings search) lists every feature and fix this build carries, newest first. It reuses the dialog's entries (title, animated visual or kind icon, author and PR link) and has a "History on GitHub" link to the build's commits.
• The dialog's "View all" now closes the dialog and opens this page instead of a GitHub compare page.

Only builds that embed the notes register the page and command. Beta builds embed them as before. electron-vite dev serve now embeds them too, from git log only and without asking GitHub, so the page can be tried locally without slowing dev startup. Production builds are unchanged.

The embedded data has no build numbers or dates, so the page groups by New and Fixes like the dialog rather than by build.

Also fixes a small issue in #57886: a visual read its theme colour only once, so switching between light and dark while it was on screen left it in the old colour. It now reads the colour again whenever the root element's theme attributes change.

How did you verify your code works?

• bun test src/updater/beta-notes.test.ts in packages/gui-extensions (15 pass), including a new test for the full list and the history link.
• bun typecheck in packages/gui-extensions and packages/desktop, and bun run lint:changed beta-notes-rich (0 problems).
• One headless HiveMind run recorded the clip below with fictional notes: the Storybook dialog, View all opening the page (the story now does this), the page in dark and light, then the real app's dev server with the notes embedded, where ⌘K → "What's new" opens Settings → What's new in beta.

Screenshots / recordings

Real time: the dialog with its visuals looping, View all, the page scrolling in dark and light, then ⌘K in the app:

The page (dark) and the dialog (dark):

The dialog's footer, before ("View all on GitHub") and after ("View all", which opens the page):

Settings → What's new in beta (dark, light):

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR