fix(ux): popover collision padding, PWA manifest, webhook toasts, portal toast, dashboard error boundary, GDPR poll backoff, empty-state CTA

Grab-bag of UX gaps from audit-pass-#2 + #3. Each one is a small,
focused fix; bundled because they touch different surfaces.

- Popover: collisionPadding={16} + responsive
  w-[min(calc(100vw-2rem),18rem)] so popovers stop clipping past the
  viewport on iPhone 12 portrait.
- public/manifest.json (was missing) + manifest reference in
  layout.tsx — PWA installability now works; icons (192/512/512-
  maskable) were already present.
- Admin webhooks page: 4 silent `// ignore` catches in load/delete/
  toggle/regenerate replaced with toast.error / toast.success. Users
  no longer see a stale list with no feedback when an op fails.
- Portal document-download button: blocking alert() → toast.error().
- src/app/(dashboard)/error.tsx: branded error boundary with retry +
  back-to-dashboard, replacing Next.js's default uncaught-error UI.
- GDPR export modal: refetchInterval was a flat 5s while the modal was
  open. Switched to a function that only polls (every 15s) when a job
  is actually pending/building; settled exports stop polling entirely.
- client-yachts-tab empty state gains a CTA wired to the existing
  Add-yacht dialog, instead of just saying "No yachts".

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/ui/popover.tsx

@@ -1,33 +1,37 @@
-"use client"
+'use client';
 
-import * as React from "react"
-import * as PopoverPrimitive from "@radix-ui/react-popover"
+import * as React from 'react';
+import * as PopoverPrimitive from '@radix-ui/react-popover';
 
-import { cn } from "@/lib/utils"
+import { cn } from '@/lib/utils';
 
-const Popover = PopoverPrimitive.Root
+const Popover = PopoverPrimitive.Root;
 
-const PopoverTrigger = PopoverPrimitive.Trigger
+const PopoverTrigger = PopoverPrimitive.Trigger;
 
-const PopoverAnchor = PopoverPrimitive.Anchor
+const PopoverAnchor = PopoverPrimitive.Anchor;
 
 const PopoverContent = React.forwardRef<
   React.ElementRef<typeof PopoverPrimitive.Content>,
   React.ComponentPropsWithoutRef<typeof PopoverPrimitive.Content>
->(({ className, align = "center", sideOffset = 4, ...props }, ref) => (
+>(({ className, align = 'center', sideOffset = 4, collisionPadding = 16, ...props }, ref) => (
   <PopoverPrimitive.Portal>
     <PopoverPrimitive.Content
       ref={ref}
       align={align}
       sideOffset={sideOffset}
+      // collisionPadding keeps the popover from clipping past the viewport
+      // edge on mobile (390px / iPad portrait). w-72 is a desktop default;
+      // on narrow viewports the calc() ceiling kicks in.
+      collisionPadding={collisionPadding}
       className={cn(
-        "z-50 w-72 rounded-md border bg-popover p-4 text-popover-foreground shadow-md outline-none data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 origin-[--radix-popover-content-transform-origin]",
-        className
+        'z-50 w-[min(calc(100vw-2rem),18rem)] rounded-md border bg-popover p-4 text-popover-foreground shadow-md outline-none data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 origin-[--radix-popover-content-transform-origin]',
+        className,
       )}
       {...props}
     />
   </PopoverPrimitive.Portal>
-))
-PopoverContent.displayName = PopoverPrimitive.Content.displayName
+));
+PopoverContent.displayName = PopoverPrimitive.Content.displayName;
 
-export { Popover, PopoverTrigger, PopoverContent, PopoverAnchor }
+export { Popover, PopoverTrigger, PopoverContent, PopoverAnchor };