fix(cli): resolve file paths correctly in diff command

[TruffleClock]

Fixes #5427

Problem

The diff command can't detect changes in components because it uses deprecated functions (fetchTree, getItemTargetPath) that add the string ui to the path twice.

• Expected path: src/ui/dialog.tsx ✅
• Actual path checked: src/ui/ui/dialog.tsx ❌

This causes the command to output "No updates found" even when local files are changed.

Solution

• Replace fetchTree → resolveRegistryItems
• Replace getItemTargetPath + path.resolve → resolveFilePath

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