feat: add wrangler email routing commands

[thomasgauvin]

Summary

Adds wrangler email routing commands wrapping the Cloudflare Email Routing REST API.

Commands

wrangler email routing
├── list                                            # List zones with email routing status
├── settings       (--zone | --zone-id)             # Get settings for a zone
├── enable         (--zone | --zone-id)             # Enable email routing
├── disable        (--zone | --zone-id)             # Disable email routing
├── dns get        (--zone | --zone-id)             # Show required DNS records
├── dns unlock     (--zone | --zone-id)             # Unlock MX records
├── rules list/get/create/update/delete             # Routing rules CRUD
├── rules catch-all get/update                      # Catch-all rule
└── addresses list/get/create/delete                # Destination addresses (account-scoped)

Key design decisions

• Zone resolution: --zone example.com (domain) or --zone-id abc123 (direct ID)
• Follows VPC command pattern: createCommand(), fetchResult()/fetchPagedListResult()
• OAuth scope: Adds email_routing:write to DefaultScopes. Bach MRs: staging / production
• Concurrency-limited list: Fetches settings per-zone with limit of 5
• Smart error handling: Distinguishes "not configured" from real API errors

Testing

• 33 unit tests, all passing
• Build passes

[changeset-bot]

🦋 Changeset detected

Latest commit: d8f9478

The changes in this PR will be included in the next version bump.

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[LuisDuarte1]

from the EMAIL team:

├── rules list/get/create/update/delete             # Routing rules CRUD
├── rules catch-all get/update                      # Catch-all rule

why do we have to have 2 seperate comands for rules that are not catch-alls and rules that are a catch-all? couldn't rules * also handle this?