docs: update the swipe limits and note what pauses or replaces a swipe

Merge-time fix for #674: the mobile-handlers.js @fileoverview still
gave the old 300 ms and 100 px limits (now 500 ms and 50 px), and the
Mobile Guide now says a visible text selection pauses the swipe and a
terminal wider than the screen pans instead of switching.

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

docs/wiki/Mobile-Guide.md

@@ -37,7 +37,8 @@ a bottom sheet rather than a dropdown. On a folding phone (iPhone Duo) dialogs s
 the hinge, and opening or closing the device is treated as the device changing shape, never
 as the keyboard appearing.
 
-**Swipe left and right** on the terminal to switch sessions.
+**Swipe left and right** on the terminal to switch sessions. A visible text selection pauses
+the swipe, and a terminal wider than the screen pans sideways instead of switching.
 
 ## The home screen