fix(terminal): improve terminal dimensions and fit timing

Use min-height:0 on xterm-wrapper (flex child) instead of height:100%
to properly fill available space in flex layout. Add delayed fit()
calls after initialization to let the layout stabilize before
calculating terminal cell dimensions.

💘 Generated with Crush

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

web/src/components/Shell.jsx

@@ -439,6 +439,12 @@ export default function Shell({ api }) {
         const entry = tabsRef.current[tab.id]
         if (entry) entry.fitAddon.fit()
       }
+      setTimeout(() => {
+        for (const tab of tabsRef.current._tabList || []) {
+          const entry = tabsRef.current[tab.id]
+          if (entry) entry.fitAddon.fit()
+        }
+      }, 150)
     })
   }, [initTerminal])
 
@@ -472,11 +478,11 @@ export default function Shell({ api }) {
       requestAnimationFrame(() => {
         if (cancelled) return
         const entry = tabsRef.current[tab.id]
-        if (entry) entry.fitAddon.fit()
+        if (entry) {
+          entry.fitAddon.fit()
+          setTimeout(() => { if (!cancelled) entry.fitAddon.fit() }, 100)
+        }
       })
-    }
-
-    for (const tab of tabs) {
       if (!tabsRef.current[tab.id]) {
         tryInitTab(tab, 0)
       }