Here's how I think it would work:

• First, the user renames a file normally using the file explorer in their editor.
• Tsserver will pick up on this change and update the project (which will break a lot of imports to the old location).
• After the rename, the editor will offer the user to update references to the file.
• If the user says yes, it will then ask tsserver to get code edits, passing in the old and new paths to the file.
• Tsserver will walk all imports, see which ones are unresolved now and could have resolved to the old path (but don't since that's been moved now), and update them to the new path instead, and send these edits to the editor.
• The editor will apply the edits to all files. (Hopefully with undo functionality if the user decides against renaming the file.)

This is a bit tricky on the tsserver side since we need to be able to figure out what unresolved imports could have resolved to. This meant I had to leave moduleResolutionCache around so we could look at the failed lookup locations for failed imports.

Fully expecting to need a lot of revision on this. CC @mjbvz for protocol review.