Terminals can't scale glyphs, so the banner now picks a layout per
column width instead of always rendering the full 101-col logo:
- Wide (>= logo width): full ASCII logo + tagline.
- Mid (>= 58 cols): centered rule banner that expands with viewport.
- Narrow (>= 34 cols): brand line + tagline, both width-aware.
- < 34 cols: hidden.
SessionPanel surfaces model/cwd/sid inline when the hero column is
hidden, so narrow layouts don't lose that info. Logo width constants
derive from the art itself.