docs(cloudflare): align troubleshooting permission ids (#119)

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## Summary

The Cloudflare troubleshooting **Forbidden** guidance still named the
old token permission strings (`zone:read`, `dns_records:edit`) after
#117 switched the canonical docs to Cloudflare’s current scope ids.

This updates that one sentence in
`apps/docs/content/guides/troubleshooting.mdx` to `zone.read` and
`dns.write`, matching `apps/docs/content/providers/cloudflare.mdx`.

A repo scan found no other leftover `zone:read` / `dns_records:edit` /
`dns_records` in docs-only files. Source and tests are untouched.

## Surfaces

- **Documentation** — troubleshooting Forbidden sentence now uses the
current Cloudflare permission ids.
- Core API, React, registry, providers, snippets, package artifacts,
host integration, and deployment: not in scope.

## Test plan

- [x] Confirm the Forbidden sentence names `zone.read` and `dns.write`
- [x] `bun run reference:check` in `apps/docs`
- [x] `./node_modules/.bin/blume validate --strict` in `apps/docs`
- [x] `bun run typecheck` in `apps/docs`
- [x] `bun run typecheck:examples` from the repo root
- [x] `bun run build` in `apps/docs`
- [x] `./node_modules/.bin/blume audit --strict` in `apps/docs`
- [x] `git diff --check`

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Co-authored-by: Cursor Agent <cursoragent@cursor.com>