0.0.10: Keep quota hover width stable beside the filename footer

Reserve the maximum terminal-cell width of the quota summary and reset countdowns. Switching to shorter hover text otherwise shifts the boundary beside the flex-growing filename, repeatedly triggering mouseout and mouseover even with a stationary pointer.

Keep updates event-driven without timers or polling. Verified stable hover across repeated OpenTUI renders, restoration on exit to the filename, repository checks, and whitespace checks.