feat(web): implement Ship List page with create and delete modals

Adds ship cards with navigation, create ship modal with initial stats,
inline delete confirmation, and supporting CSS for modals and cards.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/components/ships/ShipCard.tsx

@@ -0,0 +1,43 @@
+import { useNavigate } from 'react-router-dom';
+import type { ShipListItem } from '../../types/ship';
+
+interface Props {
+  ship: ShipListItem;
+  onDelete: (id: string) => void;
+}
+
+export default function ShipCard({ ship, onDelete }: Props) {
+  const navigate = useNavigate();
+
+  const timeAgo = formatTimeAgo(ship.updated_at);
+
+  return (
+    <div className="ship-card" onClick={() => navigate(`/ship/${ship.id}`)}>
+      <div className="ship-card-info">
+        <span className="ship-card-name">{ship.name}</span>
+        <span className="ship-card-updated">{timeAgo}</span>
+      </div>
+      <button
+        className="btn-icon ship-card-delete"
+        onClick={(e) => {
+          e.stopPropagation();
+          onDelete(ship.id);
+        }}
+        title="Delete ship"
+      >
+        &#128465;
+      </button>
+    </div>
+  );
+}
+
+function formatTimeAgo(timestamp: number): string {
+  const seconds = Math.floor((Date.now() - timestamp) / 1000);
+  if (seconds < 60) return 'just now';
+  const minutes = Math.floor(seconds / 60);
+  if (minutes < 60) return `${minutes}m ago`;
+  const hours = Math.floor(minutes / 60);
+  if (hours < 24) return `${hours}h ago`;
+  const days = Math.floor(hours / 24);
+  return `${days}d ago`;
+}