style(ui): the kit panel for every menu, shared danger rows, radio pickers (#1945)

* style(ui): the kit panel for every menu, shared danger rows, radio pickers

Every mat-menu now gets the kit panel from one global rule instead of the
opt-in `.app-menu` class: a bordered 10px panel, 36px rows at 13px with
16px icons, the checked row on the list-selection tokens. The mixin caps
the panel at 360px wide and 480px tall (less in a short window), so long
lists such as seasons and guide scopes scroll inside it; Material 22 sets
no height limit.

Destructive rows in the downloads lists and the dashboard rail card menu
use `app-menu-item--danger` after a mat-divider. The rail menu's dead
`panelClass` and private danger/separator rules are gone.

The season picker's rows are appMenuItemRadio with the check slot, and its
outer tablist role applies only in chip mode. The guide scope rows are
menuitemradio with aria-checked and the same check icon, spelled out
because ui-epg sits below ui-components. Both lose their private panel
styles. The refine menu captions and the downloads source header use the
kit's section label.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(ui): replace the stale no-height-cap menu guidance

The Single-Choice Menus section still said Material sets no max-height on
a menu, so a tall menu is clipped. The kit panel now caps every menu at
480px and scrolls; the bullet keeps the advice to open a menu of actions
whole and move a secondary group into a submenu.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* test(e2e): park the pointer before the keyboard-only refine menu steps

On the Linux and Windows runners the refine menu test found the rating
row inactive after ArrowUp, with its submenu already open. With the kit's
36px rows that row sits under the runners' resting cursor; Chromium hovers
whatever lands under a resting pointer after layout, Material opens a
submenu on hover, and ArrowUp then moved inside the thresholds. Resting a
pointer on the row locally reproduces the same failure. The test now moves
the pointer to the corner before it drives the menu from the keyboard.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

apps/electron-backend-e2e/src/catalog-sort-menus.e2e.ts

@@ -353,6 +353,12 @@ test.describe('Electron catalog sort menus', () => {
             const trigger = page.locator(
                 'app-category-content-view .refine-action'
             );
+            // Keyboard only: park the pointer away from where the menu opens.
+            // Chromium hovers whatever lands under a resting pointer after a
+            // layout change, and Material opens a submenu on hover. With 36px
+            // rows the rating row sat under the CI runners' resting cursor, the
+            // thresholds opened on their own, and ArrowUp moved inside them.
+            await page.mouse.move(0, 0);
             await trigger.focus();
             await page.keyboard.press('Enter');
             const menu = refineMenuPanel(page);