[COM-193] Lock compute provider for new deployment versions

[rossnelson]

Summary

• Resolve the compute provider already used by an existing Worker Deployment before rendering the create-version form.
• Initialize new versions with that provider and hide every alternative so a deployment cannot move providers between versions.
• Preserve the existing configurable/default provider behavior for deployments without versions.
• Fail closed when deployment loading fails or the existing provider is missing, unknown, mixed, or excluded by configuration.
• Expose canCreateServerlessDeployment so consumers can hide the empty-state serverless create action when no provider is supported, while keeping the self-managed deployment link visible.

Test plan

• Focused provider-lock tests passed during implementation (25/25).
• Pre-commit ESLint, Prettier, and Stylelint hooks passed for both commits.
• git diff --check passed.
• Static architect review approved both changes.
• CI checks pending. Per request, local test workers were not restarted after the final static-only adjustments.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
holocene	Ready	Preview, Comment	Jul 15, 2026 5:09pm

[andrewzamojc]

LGTM 👍