feat(tui): responsive banner tiers

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.

ui-tui/src/components/appLayout.tsx

@@ -112,9 +112,9 @@ const TranscriptPane = memo(function TranscriptPane({
 
               {row.msg.kind === 'intro' ? (
                 <Box flexDirection="column" paddingTop={1}>
-                  <Banner t={ui.theme} />
+                  <Banner maxWidth={Math.max(1, composer.cols - 2)} t={ui.theme} />
 
-                  {row.msg.info && <SessionPanel info={row.msg.info} sid={ui.sid} t={ui.theme} />}
+                  {row.msg.info && <SessionPanel info={row.msg.info} maxWidth={Math.max(1, composer.cols - 2)} sid={ui.sid} t={ui.theme} />}
                 </Box>
               ) : row.msg.kind === 'panel' && row.msg.panelData ? (
                 <Panel sections={row.msg.panelData.sections} t={ui.theme} title={row.msg.panelData.title} />