fix(registry): stop matching reverse-DNS namespace in search

[samuv]

Summary

• Registry search matched the full server name, including reverse-DNS namespaces like io.github.stacklok/…. Searching for common terms such as github therefore matched (almost) the entire catalog and looked broken.
• Filter on the short name (segment after the last /), plus title, description, and tags — the fields users actually see.
• Add regression tests for the namespace false-positive, short-name matching, and tag matching (existing title-search coverage kept).

Test plan

• Open Registry and type github — only GitHub-related servers remain (not the whole catalog)
• Type fetch — finds io.github.stacklok/fetch via short name
• Type a tag (e.g. a known catalog tag) — matching servers remain
• pnpm exec vitest run renderer/src/routes/__tests__/registry.test.tsx

[Copilot]

Pull request overview

Fixes Registry search behavior so it no longer matches reverse-DNS namespace prefixes (e.g. io.github.stacklok/...), which previously caused common terms like github to match most of the catalog and appear broken.

Changes:

• Update Registry filtering to search by short name (segment after the last /) plus title, description, and tags.
• Add regression tests for namespace false-positives and tag matching in Registry search.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
renderer/src/routes/(registry)/-registry.route.tsx	Adjusts search filtering fields to use short-name + user-visible fields (title/description/tags) instead of full namespaced name.
renderer/src/routes/tests/registry.test.tsx	Adds/extends regression tests covering namespaced search false-positives, short-name searching, and tag searching.

[samuv]

Addressed the follow-up review points in 1568396:

1. Fully qualified names — conscious trade-off initially, but agreed it's worth supporting. filterFields now receives the search term; when the query contains /, we also match the full namespaced name so pasting e.g. io.github.stacklok/fetch works, without reintroducing the github false-positive for bare terms. Covered by a regression test.

2. Comment — softened to "title/description (what users see) and tags (common search terms)".

3. Tags — spread as separate fields instead of join(' ').

Left the pre-existing filterFields inline-closure / useMemo point alone as out of scope.