Merge pull request #609: fix(remote): close the row gaps at the join in a remote history load

Conflict resolved in tmux-manager.ts: #609's screen-aware
joinScrollbackAndFrame keeps #602's merge-time SGR reset before the frame,
and #609's join tests expect it. The #601/#602 route test now mocks the
remote read in #609's { scrollback, screen } shape.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/web/routes/session-routes.ts

@@ -3138,7 +3138,10 @@ export function registerSessionRoutes(
         captureOpts.historyLimitLines,
         terminalBufferMaxBytes
       );
-      if (remoteScrollback !== null) captureOpts.scrollbackOverride = remoteScrollback;
+      if (remoteScrollback !== null) {
+        captureOpts.scrollbackOverride = remoteScrollback.scrollback;
+        captureOpts.scrollbackOverrideScreen = remoteScrollback.screen;
+      }
     }
     const capture = (opts: PaneCaptureOptions): string | null =>
       muxName && typeof ctx.mux.captureActivePaneBuffer === 'function'