feat(ui): unify overlay animations and trim tooltip delays

Use base-ui's transition-status pattern (data-starting-style /
data-ending-style) for Dialog, DropdownMenu, Select, Tooltip and Popover
so open/close animate consistently at 150ms ease-out without flicker.
Wrap dialog popups in a centered flex container so the scale animation
no longer fights with translate-based positioning, and switch
PendingChangesBar to a real Popover so it actually animates closed.

Convert ScheduledTaskEditorDialog from raw Radix to the shared Dialog
wrapper, give ScheduledTasksDialog a stable min-height to prevent layout
shift mid-animation, and reset NewWorktreeDialog form state on open
instead of close so fields don't empty during the close transition.

Drop tooltip delay from 700ms to 300ms globally and remove all
per-component overrides except the model/variant/agent selectors in the
chat input (600ms).

packages/ui/src/components/sections/usage/UsageSidebar.tsx

@@ -85,7 +85,7 @@ export const UsageSidebar: React.FC<UsageSidebarProps> = ({ onItemSelect }) => {
         <div className="flex items-center justify-between gap-2">
           <span className="typography-meta text-muted-foreground">{t('settings.usage.sidebar.total', { count: QUOTA_PROVIDERS.length })}</span>
           <div className="flex items-center gap-2">
-            <Tooltip delayDuration={700}>
+            <Tooltip>
               <TooltipTrigger asChild>
                 <span className="inline-flex">
                   <Checkbox