fix(dashboard): route browser wheel into inner TUI scrolling

web/src/pages/ChatPage.tsx

@@ -366,6 +366,40 @@ export default function ChatPage({ isActive = true }: { isActive?: boolean }) {
     fitRef.current = fit;
     term.loadAddon(fit);
 
+    // Single-scroll-system experiment:
+    // keep browser xterm as a display/input bridge only, and let the inner
+    // Hermes TUI own transcript scrolling.
+    //
+    // In practice, the most reliable path here is NOT terminal mouse-wheel
+    // protocol emulation — that can vary by terminal mode and parser path.
+    // The inner TUI already handles keyboard-driven transcript scrolling
+    // correctly (`Shift+Up` / `Shift+Down`, `PageUp` / `PageDown`), so we
+    // translate browser wheel gestures into those known-good key sequences.
+    term.attachCustomWheelEventHandler((ev) => {
+      if (wsRef.current?.readyState !== WebSocket.OPEN) {
+        return false;
+      }
+
+      const delta = ev.deltaY;
+      if (!delta) {
+        return false;
+      }
+
+      // Shift+Up / Shift+Down: the TUI maps these to line-by-line
+      // transcript scrolling, which feels much closer to wheel behavior
+      // than PageUp/PageDown's half-page jumps.
+      const step = Math.max(1, Math.round(Math.abs(delta) / 50));
+      const seq = delta > 0 ? "\x1b[1;2B" : "\x1b[1;2A";
+
+      for (let i = 0; i < step; i++) {
+        wsRef.current.send(seq);
+      }
+
+      ev.preventDefault();
+      ev.stopPropagation();
+      return false;
+    });
+
     const unicode11 = new Unicode11Addon();
     term.loadAddon(unicode11);
     term.unicode.activeVersion = "11";