Add Components V2 route shell

[Mbeaulne]

Tophatting

Manual tophatting recommended because this adds a new route.

1. Turn on the Components V2 beta flag.
2. Confirm the dashboard sidebar shows “Components V2”.
3. Open /components-v2.
4. Turn the flag off and confirm direct navigation redirects away.

What changed

Adds the first shell of the experimental Components V2 page.

This PR adds:

• the component-search-v2 feature flag
• the /components-v2 route
• the dashboard sidebar link when the flag is on
• the basic page header and search input

It does not add real search results yet. That comes in the next PR.

Why

This keeps routing and feature-flag review separate from the larger search implementation.

Test plan

• Turn on the Components V2 beta flag
• Confirm the dashboard sidebar shows “Components V2”
• Open /components-v2
• Turn the flag off and confirm direct navigation redirects away
• Run pnpm run typecheck --pretty false

[Mbeaulne]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Adds AI-generated component descriptions to Components V2 #2337
• Add AI rerank and detail actions to Components V2 #2323
• Add multi-source Components V2 search and filters #2322
• Add Components V2 route shell #2319 👈 (View in Graphite)
• Add component search support utilities #2318
• Extract shared component detail view #2317
• Add natural-language component rerank service #2321
• Add Agent Settings UI for AI search #2320
• Add BYOK component search settings hook #2316
• Add component search index service #2315
• master

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

🎩 Preview

A preview build has been created at: 05-27-components-v2-search-page/e2ad4c3