fix(shell): default fontSize 10px and init new tabs immediately

- Base font size reduced from 12px to 10px
- New tabs now initialize directly when added (was waiting for
  tab switch because the MutationObserver only fired on visibility
  changes, not on tab additions)
- Zoom level applied to newly created terminals

💘 Generated with Crush

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

web/src/components/Shell.jsx

@@ -350,7 +350,7 @@ export default function Shell({ api }) {
   const { t } = useI18n()
   const tabsRef = useRef({})
   const nextIdRef = useRef(1)
-  const settingsRef = useRef({ fontSize: 12, fontFamily: "'JetBrains Mono', 'Fira Code', monospace", theme: 'system' })
+  const settingsRef = useRef({ fontSize: 10, fontFamily: "'JetBrains Mono', 'Fira Code', monospace", theme: 'system' })
   const pendingCommandsRef = useRef({})
 
   const [tabs, setTabs] = useState(() => {
@@ -399,7 +399,7 @@ export default function Shell({ api }) {
   const [editingTab, setEditingTab] = useState(null)
   const [editName, setEditName] = useState('')
   const [terminalSettings, setTerminalSettings] = useState({
-    fontSize: 12,
+    fontSize: 10,
     fontFamily: "'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'SF Mono', 'Menlo', monospace",
     theme: 'system',
   })
@@ -496,7 +496,7 @@ export default function Shell({ api }) {
     api.getConfig().then(d => {
       if (d.terminal) {
         setTerminalSettings({
-          fontSize: d.terminal.font_size || 12,
+          fontSize: d.terminal.font_size || 10,
           fontFamily: d.terminal.font_family || "'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'SF Mono', 'Menlo', monospace",
           theme: d.terminal.theme || 'system',
         })
@@ -511,8 +511,9 @@ export default function Shell({ api }) {
     if (!container) return
 
     const s = settingsRef.current
+    const effectiveFontSize = s.fontSize + zoomLevel * 2
     const { term, fitAddon, searchAddon } = createTerminal(container, {
-      fontSize: s.fontSize,
+      fontSize: effectiveFontSize,
       fontFamily: s.fontFamily,
       theme: s.theme,
     })
@@ -706,6 +707,12 @@ export default function Shell({ api }) {
       })
     }
 
+    for (const tab of tabs) {
+      if (!tabsRef.current[tab.id]) {
+        tryInitTab(tab, 0)
+      }
+    }
+
     const wrapper = document.querySelector('.shell-layout')?.parentElement
     let observer
     if (wrapper) {