vercel-edge No AI integrations in the default set

`vercel-edge/src/sdk.ts:36` returns eight integrations, none of them AI. Next.js edge routes are a common place to call an LLM. `@sentry/vercel-edge` already depends on `@sentry/server-utils` and re-exports the manual `instrument*Client` helpers, so the pieces are there.

**Work item.** Investigate whether `vercelAIIntegration` can be added to the edge defaults. It may need channel injection that the edge runtime cannot do, in which case the answer is documentation, not code.

**Prior art **getsentry/sentry-javascript#22964 moved the Vercel AI integration into `@sentry/server-utils`, which is the dependency `@sentry/vercel-edge` already has. Nothing followed up on the edge defaults.

Start at vercel-edge/src/sdk.ts:36 and inspect the eight default integrations, then read the vercelAIIntegration implementation in @sentry/server-utils and the re-exported manual instrument*Client helpers. Determine whether channel injection works in the edge runtime; done means either adding the integration to the defaults with coverage or documenting why it cannot be added.

Written by the indexing model from the issue text.