feat(v0.3): keybar Claude shortcuts + scrollback search + clickable links

- keybar: add Esc·Esc / ^O / ^T / ^B + per-button tooltips (KEY_MAP 14 keys)
- M1 search: @xterm/addon-search per terminal; 🔍 toolbar button + search box
  (Enter=next, Shift+Enter=prev, Esc=close)
- M2 links: @xterm/addon-web-links per terminal (tap URLs Claude prints)
- tab bar split into #tabs (scrollable) + #toolbar (utility cluster) for future
  utilities (QR/settings/dashboard)
- Browser-verified: 14 keybar buttons, search highlights matches, no console errors.
  199 tests green, typechecks + build ok.

test/keybar.test.ts

@@ -78,10 +78,18 @@ describe('keybar', () => {
       expect(KEY_MAP.slash).toHaveLength(1)
     })
 
-    it('all 10 keys are defined', () => {
+    it('Claude Code control keys map to the right bytes', () => {
+      expect(KEY_MAP.escEsc).toBe('\x1b\x1b') // rewind / clear draft
+      expect(KEY_MAP.ctrlO).toBe('\x0f') // expand transcript
+      expect(KEY_MAP.ctrlT).toBe('\x14') // task list
+      expect(KEY_MAP.ctrlB).toBe('\x02') // background
+    })
+
+    it('all 14 keys are defined', () => {
       const keys = Object.keys(KEY_MAP)
       expect(keys).toEqual([
         'esc',
+        'escEsc',
         'shiftTab',
         'arrowUp',
         'arrowDown',
@@ -89,6 +97,9 @@ describe('keybar', () => {
         'arrowRight',
         'enter',
         'ctrlC',
+        'ctrlO',
+        'ctrlT',
+        'ctrlB',
         'tab',
         'slash',
       ])
@@ -96,8 +107,8 @@ describe('keybar', () => {
 
     it('all mapped bytes are unique strings', () => {
       const bytes = Object.values(KEY_MAP)
-      expect(bytes).toHaveLength(10)
-      expect(new Set(bytes).size).toBe(10) // all unique
+      expect(bytes).toHaveLength(14)
+      expect(new Set(bytes).size).toBe(14) // all unique
     })
 
     it('ANSI arrow sequences use correct format', () => {