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.

public/tabs.ts

@@ -206,6 +206,18 @@ export class TabApp {
     this.tabs[this.activeIndex]?.session.send(data)
   }
 
+  /** Scrollback search in the active tab (M1). */
+  findInActive(query: string, dir: 'next' | 'prev'): void {
+    const s = this.tabs[this.activeIndex]?.session
+    if (!s) return
+    if (dir === 'next') s.findNext(query)
+    else s.findPrevious(query)
+  }
+
+  clearActiveSearch(): void {
+    this.tabs[this.activeIndex]?.session.clearSearch()
+  }
+
   /* ── rendering ───────────────────────────────────────────────── */
 
   /** In-place update of one tab's classes/label/dot — never destroys the DOM. */