fix(run): stop the terminal wheel from typing arrow keys, re-attach dropped sockets

Three separate reasons the Workspace terminal looked unscrollable:

- xterm falls back, on an alt-screen buffer whose program has not enabled
  mouse tracking, to translating each wheel notch into a cursor-key press.
  Inside a `claude` pane that reads as arrow up/down, so scrolling walked the
  prompt history. A custom wheel handler returning false suppresses only that
  emulation branch; real mouse reports come from a separate listener xterm
  registers when the program does request wheel events.
- TerminalView never reconnected, so a server restart left the pane frozen on
  its last painted frame — still live-looking, but swallowing every keystroke
  and mouse report. It now re-attaches 1.5s after an unexpected close and
  stops only on the server's `exit` frame; tmux keeps the session, so the
  re-attach repaints in full.
- tmux repaints the whole pane, so xterm's own scrollback is always empty and
  its viewport scrollbar renders as a groove with no thumb that cannot move.
  Hidden, since scrolling there goes through mouse reports, not the DOM.

client/src/index.css

@@ -155,6 +155,18 @@
     display: none;
   }
 
+  /* The run console's terminal attaches to tmux, which repaints the whole pane
+     on every frame — xterm's own scrollback stays empty forever, so its
+     viewport scrollbar renders as a groove with no thumb that never moves.
+     Scrolling there goes through mouse reports to the pane's program, not the
+     DOM, so hide the dead affordance. */
+  .xterm-viewport {
+    scrollbar-width: none;
+  }
+  .xterm-viewport::-webkit-scrollbar {
+    display: none;
+  }
+
   /* Visually hidden until focused — first Tab lands here before the sidebar. */
   .skip-to-content {
     position: absolute;