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

src/web/public/terminal-ui.js

@@ -3304,9 +3304,9 @@ Object.assign(CodemanApp.prototype, {
   /**
    * Post-scroll companion to _noteTerminalUserScroll: hitting the TOP of the
    * buffer while scrolling up gives the app a chance to pull the rest of tmux's
-   * scrollback (issue #205, see _maybeRefetchFullHistory). Shell sessions decline
-   * automatic pulls because their captures can be large; their banner button is
-   * the explicit path. Must be called AFTER scrollLines(), since the check is on
+   * scrollback (issue #205, see _maybeRefetchFullHistory). Shell sessions pull a
+   * bounded window because their captures can be large; their banner button is
+   * the unbounded path. Must be called AFTER scrollLines(), since the check is on
    * the resulting position, and it is deliberately not folded into
    * _noteTerminalUserScroll for exactly that reason.
    */
@@ -3354,13 +3354,17 @@ Object.assign(CodemanApp.prototype, {
    * below the last line, and _estimateReplayRows can only approximate wrapping.
    * Only a capture that is worse by more than a full screen counts as a
    * downgrade, which leaves every genuine recovery case untouched.
+   *
+   * A caller that already estimated the capture's rows passes them as
+   * `estimatedRows`, so a megabyte capture is not scanned twice.
    */
-  _replayWouldShrinkBuffer(capture) {
+  _replayWouldShrinkBuffer(capture, estimatedRows) {
     const term = this.terminal;
     const rowsNow = term?.buffer?.active?.length || 0;
     if (!rowsNow) return false;
     const screen = term?.rows || 24;
-    return this._estimateReplayRows(capture, term?.cols) + screen < rowsNow;
+    const rows = estimatedRows ?? this._estimateReplayRows(capture, term?.cols);
+    return rows + screen < rowsNow;
   },
 
   /**