Fix react-best-practices description and broken skill examples

[roboeve]

Four small fixes to heavily used skills. Each one is a description that promises the wrong thing, an example that doesn't run, or a missing guard.

Why

• react-best-practices: the description promises a TSX checklist covering accessibility and TypeScript patterns that "triggers after editing multiple TSX components". The body and all 70 rules cover performance only, with no accessibility or TypeScript rules. The edit-count trigger came from the PreToolUse injection hook, which hooks/hooks.json no longer registers. Agents now pick skills by description alone, so the description has to say what the skill really contains.
• vercel-functions streaming example: it loops over an undefined data, sends raw chunks under text/event-stream with no SSE framing, and uses setTimeout, which this skill's own validate rules flag.
• ai-gateway references/routing.md: the fallback example hardcodes anthropic/claude-opus-5 and google/gemini-3.1-pro-preview, although SKILL.md says not to put time-sensitive model IDs in reusable examples and to choose models from /v1/models.
• marketplace: remove --yes appears in the CLI list with no warning, even though it deletes a provisioned resource and its data.

Approach

• react-best-practices/overlay.yaml: rewrite the description to match the rule categories and say what the skill does not cover. SKILL.md regenerated with bun run build:skills.
• vercel-functions: a self-contained GET SSE example with data: ...\n\n frames and Cache-Control: no-cache.
• ai-gateway: replace the hardcoded IDs with placeholders that point to /v1/models.
• marketplace: one line requiring explicit user approval before remove.

Validation

• bun run typecheck && bun test: 1079 pass, 0 fail
• bun run validate: passed
• bun run build:skills:check: 0 stale

---

Update (@molebox)

Rebased onto main and fixed the review findings against the shipped vercel@64.5.0 CLI and upstream vercel-labs/agent-skills.

• Marketplace warning: this PR's new warning was on the wrong command. vercel integration resource remove (aliases integration-resource remove, ir rm) permanently deletes a resource, and refuses while projects are connected unless you pass --disconnect-all. vercel integration remove only uninstalls, and fails while resources remain. Both still need user approval.
• react-best-practices: the description now lists all 8 rule categories. Removed the retrieval terms that contradicted "not an accessibility guide" (check accessibility, accessibility, tsx linter). The 70-rule count matches the rule files, and the local copy is identical to upstream main. tests/external-skill-resolution.test.ts required the word "accessibility". It now checks that the rule count matches the files and that the retrieval metadata doesn't mention accessibility.
• vercel-functions SSE example: a GET handler that reads no request data is prerendered at build time when Cache Components is on (Next 16.5 route-handler docs). The example now reads jobId from request.url, so it stays request-time.
• ai-gateway placeholders: the old model IDs were valid. This change follows the "no time-sensitive IDs" rule; it doesn't fix a broken example.

Checks: build:*:check, validate, and bun run test all pass.