feat(ui): portable, resizable rail panels for CCTV

A drag spec can now be `portable`: dragging the panel by its header lifts
it out of the right rail into a fixed window, resizable from all four
edges and corners, that remembers its place and size under the existing
godsEyeView.v8.panelPos.<id> key ({ left, top, width?, height?, floating })
and snaps back on a header double-click. Only CCTV opts in here; the rail
skips .panel-floating panels when measuring and allocating, and its
placement rules in layers.css are guarded so no !important is needed.
PanelPositionControls gains an optional onPanelResized hook, threaded
through PanelChrome to a no-op on the application shell.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

src/ui/applicationShell.js

@@ -96,6 +96,7 @@ export class StyleManager extends ShellFacade {
         _setRadioDisclosure: (...args) => this._setRadioDisclosure(...args),
         _syncCctvPanelViewport: (...args) =>
           this._syncCctvPanelViewport(...args),
+        _onPanelResized: (...args) => this._onPanelResized(...args),
         _syncContextRadioLauncherState: (...args) =>
           this._syncContextRadioLauncherState(...args),
         _showToast: (...args) => this._showToast(...args),
@@ -1409,6 +1410,15 @@ export class StyleManager extends ShellFacade {
     this._initCockpitDisplayPortal();
   }
 
+  /**
+   * A portable panel finished a resize or snapped back to its rail. Nothing
+   * in the shell depends on it yet; a panel with a viewport of its own can
+   * refit here.
+   * @param {string} _panelId
+   * @returns {void}
+   */
+  _onPanelResized(_panelId) {}
+
   /**
    * Recalculates the CCTV panel max-height based on its current top position
    * and the window height, enabling internal scroll without viewport overflow.