fix(change-ledger): keep counts, ages and titles whole on desktop

[arasovic]

Same desktop fix as #5, for the change-ledger pane.

• Desktop and other non-terminal surfaces: line counts, "new", the edit count and age, ahead and behind, and each frame's title no longer shrink.
• Only the free text gives way: file paths, folders, the agent list, the branch name and a frame's right label.
• The edit's second line splits the agent list from "· 3× · 1m ago", so a long list of agents cannot push out the count and age.
• The terminal grid is unchanged.
• A new test draws the pane on desktop from a set state and checks that the long parts arrive whole and that the numbers and titles sit in boxes that do not shrink. It fails on the previous code.
• Version 0.1.5.