vercel-edge: Missing exports

Present in `@sentry/cloudflare`, absent from `@sentry/vercel-edge`: `vercelAIIntegration`, `updateSpanName`, `setConversationId`, `growthbookIntegration`, `spotlightIntegration`, `prismaIntegration`, `instrumentCreateReactAgent`, `httpServerIntegration`.

`vercelAIIntegration` missing from the Vercel edge runtime is the odd one.

**Work item.** Add the re-exports that apply. For any that genuinely do not work on the edge runtime, leave a comment in `index.ts` saying why.

Compare the exports in @sentry/cloudflare with the Vercel Edge package's index.ts, focusing on the integrations and helpers listed in the issue. Add re-exports that work in the edge runtime, and document any excluded exports in index.ts with the reason. Verify that the package exposes the applicable names without including incompatible ones.

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