Show current root Git status before resuming saved history #64

Part of #4.

Show the selected root Git branch and changed-file counts alongside saved history before Resume or Fork. Reuse the existing workspace status panel, distinguish current files from saved conversation context, and keep unavailable or failed inspections explicit.

Reviewing changes must preserve the selected archive entry and continuation draft. Cover that round trip and focus refresh in Electron, including a native-window screenshot. This slice does not change resume semantics or block continuation on dirty work.