Improve edge-docked window behavior (#2779)

* Make edge-docked windows resizable

Add draggable resize seams for left and right docked windows.

Keep the main chat area from getting too narrow and remember each window's dock width.

* Show emoji shortcodes as icons by default

Keep text-only emoji mode opt-in so model output like 😊 goes through the normal emoji renderer.

* Fix dock resize seams and left dock layout

Hide the resize seam when another floating modal is open, and keep the left-docked window from covering the chat area.

* Keep narrow modal tabs usable

* Fix split layout with both edge docks

* Fix left snap after right dock

* Enable left edge snap for all windows

* Tighten dock resize handle observers

* Use edge docking for settings window

static/js/settings.js

@@ -53,7 +53,7 @@ function initDrag() {
     content,
     header,
     skipSelector: 'button, input, select, .theme-opacity-wrap',
-    enableDock: false,
+    enableDock: true,
   });
 }