refactor(frontend): migrate Bash, Log, and Deploy feedback dialogs (#952)

- modal.tsx Modal now accepts a showClose prop that passes through to
  DialogContent, so callers that render their own close affordance
  (DeployFeedbackModal) can suppress the Radix close button
- DeployFeedbackModal -> Modal with showClose=false. Custom header,
  scroll body, embedded terminal, and footer stay in place; Modal
  provides the consistent overlay/blur chrome. DialogTitle is still
  imported from the dialog primitive purely as an sr-only
  accessibility wrapper, since this status panel doesn't fit the §10
  ModalHeader chrome
- BashExecModal -> Modal + ModalHeader. Kicker BASH · {CONTAINER}.
  The xterm container sits in the body
- LogViewer -> Modal + ModalHeader. Kicker LOGS · {CONTAINER}. The
  scroll region sits in the body

frontend/src/components/ui/modal.tsx

@@ -34,12 +34,15 @@ interface ModalProps {
   children: React.ReactNode;
   size?: ModalSize;
   className?: string;
+  /** Pass through to DialogContent — set to false when the modal renders its own close affordance. */
+  showClose?: boolean;
 }
 
-export function Modal({ open, onOpenChange, children, size = 'md', className }: ModalProps) {
+export function Modal({ open, onOpenChange, children, size = 'md', className, showClose }: ModalProps) {
   return (
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent
+        showClose={showClose}
         className={cn(
           'p-0 gap-0 overflow-hidden grid-cols-1',
           SIZE_CLASS[size],