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/chat/ModelControls.tsx

@@ -2654,7 +2654,7 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
         let currentFlatIndex = 0;
 
         return (
-            <Tooltip delayDuration={1000}>
+            <Tooltip delayDuration={600}>
                 {!isCompact ? (
                     <DropdownMenu open={isReady && agentMenuOpen} onOpenChange={isReady ? handleModelMenuOpenChange : undefined}>
                         <TooltipTrigger asChild>
@@ -3119,7 +3119,7 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
         }
 
         return (
-            <Tooltip delayDuration={800}>
+            <Tooltip delayDuration={600}>
                 <DropdownMenu>
                     <TooltipTrigger asChild>
                         <DropdownMenuTrigger asChild>
@@ -3182,7 +3182,7 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
         if (!isCompact) {
             return (
                 <div className="flex items-center gap-2 min-w-0">
-                    <Tooltip delayDuration={1000}>
+                    <Tooltip delayDuration={600}>
                         <DropdownMenu open={isReady && isAgentSelectorOpen} onOpenChange={isReady ? setIsAgentSelectorOpen : undefined}>
                             <TooltipTrigger asChild>
                                 <DropdownMenuTrigger asChild>