feat(v0.2): multi-tab terminal + titles + Claude Code shortcut bar

Frontend feature (backend unchanged — manager was already multi-session):
- Multi-tab: each tab = independent WS + Terminal + session (terminal-session.ts,
  tabs.ts); tab bar with +, ×, middle-click close; persisted to localStorage
  (migrates v0.1 single-session key)
- Tab titles: auto from xterm onTitleChange (OSC 0/2), double-click to rename
  inline (manual wins over auto); ellipsis + tooltip
- Shortcut key bar now shown on ALL devices (clickable buttons trigger shortcuts),
  reordered for Claude Code (Esc prominent, ⇧Tab, ↑↓, ⏎, ^C, Tab, ←→, /);
  responsive sizing via @media (pointer:coarse) for touch
- Verified in browser: rename, two independent sessions, keybar on desktop +
  narrow viewport. 191 tests green; both typechecks + esbuild build pass.

public/keybar.ts

@@ -1,19 +1,19 @@
 /**
- * public/keybar.ts — Mobile touch key bar for terminal input (T10).
+ * public/keybar.ts — Mobile touch key bar, tuned for Claude Code.
  *
  * Exports pure key-to-byte mappings and a mount function that binds DOM buttons
- * to onSend callback on touchstart (bypassing xterm to avoid soft keyboard popup).
+ * to onSend on touchstart (bypassing xterm so the soft keyboard doesn't pop up).
  *
- * Key bytes (ARCHITECTURE §5):
- *   Esc → \x1b (0x1B)
- *   Shift+Tab → \x1b[Z
- *   ↑ → \x1b[A
- *   ↓ → \x1b[B
- *   ← → \x1b[D
- *   → → \x1b[C
- *   Enter → \r (0x0D, not \n)
- *   Ctrl+C → \x03 (0x03)
- *   Tab → \t (0x09)
+ * Order/selection follows Claude Code mobile habits — the keys a phone soft
+ * keyboard can't easily produce, most-used first (leftmost = no scroll needed):
+ *   Esc        \x1b     interrupt Claude / dismiss          (primary — most used)
+ *   Shift+Tab  \x1b[Z   cycle plan / auto-accept mode
+ *   ↑ ↓        \x1b[A/B select menu option / history
+ *   Enter      \r       confirm
+ *   Ctrl+C     \x03     cancel / quit
+ *   Tab        \t       complete / toggle
+ *   ← →        \x1b[D/C cursor
+ *   /          /        slash-command launcher
  */
 
 import type { MountKeybar } from '../src/types.js'
@@ -29,46 +29,47 @@ export const KEY_MAP = {
   enter: '\r',
   ctrlC: '\x03',
   tab: '\t',
+  slash: '/',
 } as const
 
 export type KeyName = keyof typeof KEY_MAP
 
+/** Button layout: most-used Claude Code keys first. `primary` styles a key as prominent. */
+export const KEYBAR_BUTTONS: Array<{ label: string; keyName: KeyName; primary?: boolean }> = [
+  { label: 'Esc', keyName: 'esc', primary: true },
+  { label: '⇧Tab', keyName: 'shiftTab' },
+  { label: '↑', keyName: 'arrowUp' },
+  { label: '↓', keyName: 'arrowDown' },
+  { label: '⏎', keyName: 'enter' },
+  { label: '^C', keyName: 'ctrlC' },
+  { label: 'Tab', keyName: 'tab' },
+  { label: '←', keyName: 'arrowLeft' },
+  { label: '→', keyName: 'arrowRight' },
+  { label: '/', keyName: 'slash' },
+]
+
 /** Mount the key bar: create buttons in #keybar, bind touchstart → onSend(bytes) + preventDefault. */
 export const mountKeybar: MountKeybar = (onSend) => {
   const keybarEl = document.getElementById('keybar')
   if (!keybarEl) return
 
-  // Button labels and their key map entries
-  const buttons: Array<{
-    label: string
-    keyName: KeyName
-  }> = [
-    { label: 'Esc', keyName: 'esc' },
-    { label: 'Shift+Tab', keyName: 'shiftTab' },
-    { label: '↑', keyName: 'arrowUp' },
-    { label: '↓', keyName: 'arrowDown' },
-    { label: '←', keyName: 'arrowLeft' },
-    { label: '→', keyName: 'arrowRight' },
-    { label: 'Enter', keyName: 'enter' },
-    { label: 'Ctrl+C', keyName: 'ctrlC' },
-    { label: 'Tab', keyName: 'tab' },
-  ]
-
-  for (const { label, keyName } of buttons) {
+  for (const { label, keyName, primary } of KEYBAR_BUTTONS) {
     const btn = document.createElement('button')
     btn.textContent = label
     btn.classList.add('keybar-btn')
+    if (primary) btn.classList.add('keybar-btn-primary')
     btn.dataset.key = keyName
+    btn.setAttribute('aria-label', label)
 
     const bytes = KEY_MAP[keyName]
 
-    // touchstart: send immediately, prevent default to avoid soft keyboard
+    // touchstart: send immediately, prevent default so the soft keyboard stays hidden.
     btn.addEventListener('touchstart', (e) => {
       e.preventDefault()
       onSend(bytes)
     })
 
-    // For desktop testing/fallback: click also sends
+    // Desktop fallback: click also sends.
     btn.addEventListener('click', (e) => {
       e.preventDefault()
       onSend(bytes)