fix(tabs): let a wrapped desktop tab strip grow the header instead of clipping itself

The fixed 120px/96px caps on the two wrapped layouts were row counts in disguise: a
third row was clipped into a ~4px scroller, hiding tabs inside a container nothing
invites you to scroll, while the header had the page below it to grow into. Both
layouts now share one rule capped at var(--tab-strip-max-height, 40vh), a safety net
for an absurd session count rather than a row limit.

Verified before shipping: .header is min-height + flex-shrink: 0 so it can grow, and
terminal-ui's ResizeObserver refits the terminal when it does; updateTabOverflowMode()
returns early for any non-desktop viewport, and below 1024px mobile.css pins the header
to max-height: 48px, so this is desktop-only in effect; the selector is comma-grouped
rather than :is(), so each arm keeps (0,2,0) and mobile.css's overrides still win on
source order. PostCSS parses the file cleanly (prettier ignores styles.css).

Authored in a parallel session against this shared checkout.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.changeset/d3c38a94.md

@@ -0,0 +1,24 @@
+---
+"aicodeman": patch
+---
+
+fix(tabs): let a wrapped desktop tab strip grow the header instead of clipping itself
+
+The wrapped tab strip carried fixed height caps (120px for the manual two-row layout,
+96px for measured auto-wrap) that were row counts in disguise. A third row of tabs was
+clipped into a roughly 4px scroller, so the tab being looked for sat off-screen inside a
+container nothing invites you to scroll, while the header had the whole page below it to
+grow into. The header is `min-height` plus `flex-shrink: 0`, and terminal-ui's
+ResizeObserver refits the terminal on its own, so growing it costs nothing.
+
+Both wrapped layouts now share one rule capped at `var(--tab-strip-max-height, 40vh)`.
+That cap is a safety net for an absurd session count rather than a row limit: past it the
+scroller comes back, which still beats a header that swallows the terminal. Nothing sets
+`--tab-strip-max-height` yet, so today it is the 40vh fallback plus a hook for a future
+control.
+
+Desktop only in effect. `tabs-auto-wrap` is applied by `updateTabOverflowMode()`, which
+returns early for anything that is not a desktop viewport, and below 1024px `mobile.css`
+pins the header to `max-height: 48px` so it cannot grow at all. The two rules are
+comma-grouped rather than wrapped in `:is()`, so each arm keeps its own (0,2,0)
+specificity and `mobile.css`'s matching overrides still win on source order.

src/web/public/styles.css

@@ -545,18 +545,21 @@ body {
   contain: layout;
 }
 
-.session-tabs.tabs-two-rows {
+/* A wrapped strip GROWS the header instead of scrolling inside it. The old
-  flex-wrap: wrap;
+   fixed caps (120px tall-tabs / 96px auto-wrap) were row counts in disguise:
-  overflow-x: hidden;
+   a third row of tabs was clipped into a 4px scroller, so the tabs you were
-  overflow-y: auto;
+   looking for were off-screen in a container nothing tells you to scroll —
-  max-height: 120px;
+   while the header had the whole page below it to grow into (it is
-}
+   `min-height` + `flex-shrink: 0`, and terminal-ui's ResizeObserver refits
-
+   the terminal on its own). `--tab-strip-max-height` is a safety net for an
+   absurd session count, not a row limit: past it the scroller comes back,
+   which beats a header that swallows the terminal. */
+.session-tabs.tabs-two-rows,
 .session-tabs.tabs-auto-wrap {
   flex-wrap: wrap;
   overflow-x: hidden;
   overflow-y: auto;
-  max-height: 96px;
+  max-height: var(--tab-strip-max-height, 40vh);
 }
 
 .session-tabs::-webkit-scrollbar {