* Port the docs language-chooser redesign to the registry

Ports pulumi/docs#19940: language choosers now render as a card with a
gray toolbar (active language logo + name on the left, compact
file-extension tabs on the right), and a chooser missing the user's
preferred language falls back display-only instead of clobbering the
page-wide selection. Also syncs the earlier docs chooser changes (OPA,
OCI, pythontoolchain, subscribeToStore flash fix) to eliminate theme
divergence.

Additionally, per follow-up direction:
- Adopt the Min Light code theme site-wide (docs/_code-light.scss,
  imported unlayered; the registry has no dark-mode toggle)
- Adopt the _notes.scss changes (info notes violet -> blue, icon
  scoping fixes)
- Copy button becomes a ghost button with the tooltip on the left
- New language icons and the official purple C# logo

Registry-specific fixes needed along the way:
- Guard the GrowthBook/analytics init in util.ts so pages without the
  injected globals (e.g. component test pages) don't crash; this also
  fixes five pre-existing e2e suite failures
- Add pythontoolchain to normalizeState in store/index.ts
- Bump puppeteer to ^24 (required by Stencil 4.43 to run e2e tests)
- Fix the upstream chooser toolbar e2e test by initializing the store
  via pulumi-root (it fails as-written in pulumi/docs too)
- Hide the .docs-logo-dark toolbar logo variant (no dark theme here)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Make the language chooser code block flush with its toolbar

In the flush "code-only" language chooser (e.g. the Example block on a
package overview page), a 16px gap appeared between the gray toolbar and
the code panel. The card's base rule zeroed only the pre's margin-bottom
(mb-0); the registry's base pre also carries a top margin, which leaked
past the toolbar. Zero both (my-0) so the .highlight wrapper remains the
sole source of vertical spacing, as intended — matching docs, where the
base pre has no top margin to begin with.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Make standalone chooser code blocks sit flush with their toolbar

On API-doc pages the language chooser is emitted in its standalone form
(a self-closing <pulumi-chooser> with the code choosables as siblings on
the page, so one chooser can drive a whole section). That renders the
chooser as a flat toolbar strip, but the adopted code block kept its 16px
top margin, leaving it detached from the toolbar above — the chooser card
rules only reach code nested inside the chooser.

Pull the first code block in an adopted language choosable flush to the
toolbar so the two read as one connected panel. Scoped with
`:not(pulumi-chooser *)` so the nested overview-card choosables, whose
spacing the card rules already handle, are untouched.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Move the code copy button to the upper-right corner, matching docs

The registry had positioned the copy button inset from the corner
(top/right: 20px, plus a margin). Match docs by pinning it flush to the
top-right corner (top/right: 0, no margin), keeping the registry's
padding and hover styling.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Give the copy button an opaque bg and docs-matched padding

Two tweaks to the code copy button:
- Opaque violet-50 background on the container (in the light code theme)
  so it masks the code and scrollbar beneath it instead of letting them
  show through a transparent button; violet-100 on hover as before.
- Match docs' sizing: 14px icon with padding 8px 8px 8px 10px on the
  button itself (the registry had shrunk it to 12px with tighter padding
  on the container), so it no longer reads smaller/cramped than docs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Restyle chooser badges and add pythontoolchain choosable support

Update badge styling to match the docs (mono, normal weight, tighter
padding), clean up chooser toolbar SCSS, and handle the pythontoolchain
selection type in the choosable component.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* Click language chooser tabs by short label in browser tests

The chooser redesign renders language tabs with short labels (uppercased
file extension, or an override like C#) instead of the full language name,
which now lives in the toolbar label. Update the Cypress tests to click
tabs by the new label so the per-language example/input assertions match.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* Address review: drop unrelated go.mod/C# logo changes, fix nit

- Revert the stray go.mod indirect require for themes/default: no Go code
  in the root module imports it and there's no go.sum entry, so it was a
  spurious `go mod tidy` artifact unrelated to the chooser work.
- Revert the logos/tech/{c-sharp,csharp}.svg swap: these files are not
  referenced anywhere in the registry, and the chooser uses a different
  icon (images/docs/icons/languages/csharp-color-32-32.svg), so the swap
  was unrelated scope creep with no visual effect.
- Add the missing trailing semicolon on PreferencesState.pythontoolchain.

Puppeteer stays at ^24: CI/mise Node is 24, which satisfies it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* Delete unused C# tech logos

logos/tech/c-sharp.svg and csharp.svg are referenced nowhere in the
registry (the chooser uses images/docs/icons/languages/csharp-color-32-32.svg),
so remove the dead assets rather than carry them.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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Co-authored-by: Claude Fable 5 <noreply@anthropic.com>