Remove deprecated shopify theme serve command

[alfonso-noriega]

WHY are these changes introduced?

The shopify theme serve command was a hidden alias for shopify theme dev. It rendered a "shopify theme serve" command is deprecated warning and forwarded the call. This PR removes the deprecated alias in preparation for the next major release.

This is the last PR in the deprecated-flag-removal stack: #7526 ← this PR. (Theme-related changes are intentionally placed at the end of the stack.)

WHAT is this pull request doing?

• Deletes packages/theme/src/cli/commands/theme/serve.ts (the Serve class).
• Removes the import and the 'theme:serve' entry from packages/theme/src/index.ts.
• Regenerates packages/cli/oclif.manifest.json (the entry is removed from the manifest).
• The supported shopify theme dev command (and its tests) are unchanged.

How to test your changes?

1. Run pnpm shopify theme serve --help and confirm it now fails with Command theme:serve not found.
2. Run pnpm shopify theme dev --help and confirm the supported command still works.
3. Run pnpm shopify theme dev against a theme and confirm the local dev server starts as before.

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

[alfonso-noriega]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Remove deprecated shopify theme serve command #7527 👈 (View in Graphite)
• Remove deprecated top-level shopify webhook trigger alias #7526
• Remove deprecated shopify app scaffold extension command #7525
• Remove deprecated shopify app generate schema command #7524
• Remove deprecated --type flag from shopify app generate extension #7523
• Remove deprecated --shared-secret flag from shopify app webhook trigger #7522
• Remove deprecated --force flag from shopify app release #7521
• Remove deprecated --force flag from shopify app deploy #7520
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

⚠️ Potential Breaking Changes Detected

This PR contains changes that may break the existing contract.

@shopify/dev_experience — this PR contains breaking changes that require coordination for the next major release. This check will remain failed until a member of the team approves the workflow run.

💬 Head to #help-dev-platform to discuss timing and plan the release.

📦 Major Version Changesets

The following changesets request a major version bump:

Changeset	Package
remove-app-deploy-force-flag.md	'@shopify/app': major
remove-app-generate-extension-type-flag.md	'@shopify/app': major
remove-app-generate-schema-command.md	'@shopify/app': major
remove-app-release-force-flag.md	'@shopify/app': major
remove-app-scaffold-extension-command.md	'@shopify/app': major
remove-theme-serve-command.md	'@shopify/theme': major
remove-top-level-webhook-trigger-alias.md	'@shopify/app': major
remove-webhook-trigger-shared-secret-flag.md	'@shopify/app': major
thin-webs-notice.md	'@shopify/plugin-did-you-mean': major
thin-webs-notice.md	'@shopify/plugin-cloudflare': major
thin-webs-notice.md	'@shopify/create-app': major
thin-webs-notice.md	'@shopify/cli-kit': major
thin-webs-notice.md	'@shopify/store': major
thin-webs-notice.md	'@shopify/theme': major
thin-webs-notice.md	'@shopify/app': major
thin-webs-notice.md	'@shopify/cli': major
thin-webs-notice.md	'@shopify/e2e': major

🗑️ Removed Commands

The following commands were removed from the OCLIF manifest:

• theme:serve