Merge pull request #494 from timkjr/fix/shell-scroll-history

fix(terminal): let a Shell pane's scroll-up reach tmux history

# Conflicts:
#	docs/wiki/The-Dashboard.md

docs/wiki/The-Dashboard.md

@@ -151,8 +151,9 @@ Worth knowing:
 
 - **Scrollback.** Agent/TUI sessions pull their entire tmux scrollback on first open.
   Shell sessions open from a bounded recent tail so a large transcript cannot stall tab
-  switching; press **Load full history** to pull the rest explicitly. Ordinary Shell scrolling
-  and automatic output recovery stay within the bounded browser buffer.
+  switching. Scrolling to the top of a Shell pane pulls the most recent 1 MiB of its tmux
+  history; press **Load full history** to pull the rest explicitly. Automatic output
+  recovery stays within the bounded browser buffer.
 - **Wheel and touch scrolling** are forwarded into Claude's own transcript when a recent
   Claude runs fullscreen, so the wheel scrolls the conversation rather than the terminal.
   Claude's default inline view keeps its history in the terminal and scrolls locally. `Shift+Wheel` is