feat: polish theme tooling, diagnostics and launcher workflows

Expand the theme editor with multi-select, snapping, context menus, draft
recovery and export validation; add theme backups and trust prompts. Add
in-app diagnostics and rotating log bundle viewing, hardware-accelerated
theme video playback on macOS, and refresh the settings, setup wizard and
theme gallery layouts.

src/lib/components/ui/context-menu/index.ts

@@ -0,0 +1,52 @@
+import CheckboxItem from './context-menu-checkbox-item.svelte';
+import Content from './context-menu-content.svelte';
+import GroupHeading from './context-menu-group-heading.svelte';
+import Group from './context-menu-group.svelte';
+import Item from './context-menu-item.svelte';
+import Label from './context-menu-label.svelte';
+import Portal from './context-menu-portal.svelte';
+import RadioGroup from './context-menu-radio-group.svelte';
+import RadioItem from './context-menu-radio-item.svelte';
+import Separator from './context-menu-separator.svelte';
+import Shortcut from './context-menu-shortcut.svelte';
+import SubContent from './context-menu-sub-content.svelte';
+import SubTrigger from './context-menu-sub-trigger.svelte';
+import Sub from './context-menu-sub.svelte';
+import Trigger from './context-menu-trigger.svelte';
+import Root from './context-menu.svelte';
+
+export {
+  Root,
+  Sub,
+  Portal,
+  Item,
+  GroupHeading,
+  Label,
+  Group,
+  Trigger,
+  Content,
+  Shortcut,
+  Separator,
+  RadioItem,
+  SubContent,
+  SubTrigger,
+  RadioGroup,
+  CheckboxItem,
+  //
+  Root as ContextMenu,
+  Sub as ContextMenuSub,
+  Portal as ContextMenuPortal,
+  Item as ContextMenuItem,
+  GroupHeading as ContextMenuGroupHeading,
+  Group as ContextMenuGroup,
+  Content as ContextMenuContent,
+  Trigger as ContextMenuTrigger,
+  Shortcut as ContextMenuShortcut,
+  RadioItem as ContextMenuRadioItem,
+  Separator as ContextMenuSeparator,
+  RadioGroup as ContextMenuRadioGroup,
+  SubContent as ContextMenuSubContent,
+  SubTrigger as ContextMenuSubTrigger,
+  CheckboxItem as ContextMenuCheckboxItem,
+  Label as ContextMenuLabel,
+};