fix: only the active service renders — wrong page shown, and slowness

Clicking WhatsApp left Claude on screen while the address bar said
web.whatsapp.com, and the app felt sluggish. Same cause for both.

`.pane webview` declared `visibility: visible`. CSS visibility inherits, and
an explicit `visible` on a child overrides a hidden ancestor — so every
webview un-hid itself inside its hidden pane. All services rendered at once,
stacked absolutely, and you saw whichever painted last. Chromium also never
throttled them, since none were occluded.

Measured before: four panes, four webviews `visible`, all full size.
After: exactly one visible, three hidden, CPU 0% across the board.

Also removes the global `webview { visibility: hidden }` / `webview.active`
rules. They predate the pane wrapper and key off a class nothing sets any
more; with the child rule gone they were hiding the active service too.

Verified through single view, split, spotlight, back to single, and clicking
each service in turn.

Author: viny4

package-lock.json

@@ -1,7 +1,7 @@
 {
   "name": "panebox",
   "productName": "Panebox",
-  "version": "2.2.0",
+  "version": "2.2.1",
   "description": "A small, private, open-source desktop deck for your web apps — AI tools, chat, mail and more in one window.",
   "main": "main.js",
   "license": "MIT",

package.json

@@ -220,11 +220,9 @@ body.platform-darwin #sidebar { padding-top: 44px; }
 #view-wrap { flex: 1; display: flex; position: relative; overflow: hidden; }
 #view-container { flex: 1; position: relative; overflow: hidden; background: var(--bg); }
 
-webview {
-  position: absolute; inset: 0; width: 100%; height: 100%;
-  border: none; visibility: hidden;
-}
-webview.active { visibility: visible; }
+/* Visibility is owned by the pane wrapper now — see `.pane` below. The old
+   rules here predated panes and still keyed off `.active` on the webview
+   itself, which nothing sets any more. */
 
 /* ------------------------------------------------------------ todo panel */
 
@@ -632,7 +630,11 @@ body.reordering webview { pointer-events: none; }
      paints, so the header appeared to exist and then vanish. */
   position: relative; inset: auto;
   flex: 1; min-height: 0; width: 100%; height: auto;
-  border: none; visibility: visible;
+  border: none;
+  /* Deliberately no `visibility` here. It inherits, so declaring `visible` let
+     every webview un-hide itself inside its hidden pane: all services rendered
+     at once, stacked, and you saw whichever painted last rather than the one
+     you clicked. It also meant Chromium never throttled the background ones. */
 }
 .pane-head { display: none; }