Enable every Aspire AppHost language

[David Pine (IEvangelist)]

Stack 5/5. Depends on #1637.

This final activation change flips the four shared registry bits that publish Python, Go, Java, and Rust everywhere automatically. All four languages remain marked Experimental, and the single-registry-bit contract provides a one-bit rollback or toggle.

The activated registry now drives selectors, tabs, pivots, sidebar navigation, search, AppHost API routes and Markdown, integrations gallery links, project and sample pages, media, builder surfaces, homepage content, sample metadata, and container labels. SimpleAppHostCode continues to render explicit limitations for unauthored language variants instead of fallback code.

Validation:

• 548 unit tests passed in the validated final state; the requested focused activation run passed 252 tests across apphost-languages, apphost-language-coverage, apphost-language-docs-loader, integration parity, diagnostics-language, api-markdown, update-samples, and custom-components.
• Full twoslash validation passed.
• Lint and Astro sync passed.
• AppHost API generator validation passed 36/36.
• 28 activated browser scenarios passed on tablet/mobile.
• 28 desktop browser cases passed across split runs.
• 3 homepage model-story viewports passed.
• 13 API Markdown routes passed.
• Mobile AppHost API search passed.
• git diff --check passed.

No local production build was run.

[Copilot]

🟡 Changes recommended

Several updated unit tests use optional-chained registry lookups (?.enabled) that can silently treat missing config entries as “disabled,” weakening test correctness and diagnostics.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR completes the “enable every Aspire AppHost language” rollout by flipping the shared AppHost language registry bits for Python/Go/Java/Rust and aligning unit/E2E coverage and a key rendering component to follow the registry-driven enablement model across the site.

Changes:

• Enables Python, Go, Java, and Rust in the shared AppHost language registry (apphost-languages.json).
• Updates multiple unit and Playwright E2E tests to assert behavior based on the registry’s enabled bits rather than hard-coded language assumptions.
• Updates SimpleAppHostCode to always render via AppHostTabs and provide limitations for unauthored language variants.

File summaries

File	Description
src/frontend/tests/unit/update-samples.vitest.test.ts	Makes sample AppHost enablement assertions reflect registry activation.
src/frontend/tests/unit/custom-components.vitest.test.ts	Adjusts component rendering tests to follow registry-enabled language set and limitations behavior.
src/frontend/tests/unit/apphost-languages.vitest.test.ts	Updates registry unit tests and normalization/link behavior to depend on enabled bits.
src/frontend/tests/unit/api-markdown.vitest.test.ts	Validates API markdown headings based on enabled generated languages.
src/frontend/tests/e2e/pivot-selector.spec.ts	Updates pivot/tab/media E2E expectations to be registry-driven.
src/frontend/tests/e2e/integrations-gallery.spec.ts	Updates integration gallery language-link assertions to be registry-driven.
src/frontend/src/data/apphost-languages.json	Flips enabled: true for Python/Go/Java/Rust.
src/frontend/src/components/SimpleAppHostCode.astro	Renders code via AppHostTabs and emits limitations for missing variants.

Review details

• Files reviewed: 8/8 changed files
• Comments generated: 3
• Review effort level: Lite

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[aspire-repo-bot]

Frontend HTML artifact ready

The latest frontend build uploaded the frontend-dist artifact for PR #1638. Use the VS Code button below to open this PR with GitHub Artifacts Explorer and browse the built HTML locally.

This comment updates automatically when a new frontend build artifact is uploaded.