feat: upgrade empty states with welcome message and column placeholders

src/components/board/KanbanColumn.tsx

@@ -99,6 +99,11 @@ export function KanbanColumn({ column, onCardClick }: KanbanColumnProps) {
                 </li>
               );
             })}
+            {column.cardIds.length === 0 && (
+              <li className="flex min-h-[60px] items-center justify-center rounded-md border border-dashed border-pylon-text-secondary/20 text-xs text-pylon-text-secondary/50">
+                Drop or add a card
+              </li>
+            )}
           </ul>
         </ScrollArea>
       </SortableContext>

src/components/boards/BoardList.tsx

@@ -24,14 +24,20 @@ export function BoardList() {
   if (boards.length === 0) {
     return (
       <>
-        <div className="flex h-full flex-col items-center justify-center gap-4">
-          <p className="font-mono text-sm text-pylon-text-secondary">
-            Create your first board
-          </p>
-          <div className="flex items-center gap-2">
-            <Button onClick={() => setDialogOpen(true)}>
+        <div className="flex h-full flex-col items-center justify-center gap-6">
+          <div className="text-center">
+            <h2 className="font-heading text-2xl text-pylon-text">
+              Welcome to OpenPylon
+            </h2>
+            <p className="mt-2 max-w-sm text-sm text-pylon-text-secondary">
+              A local-first Kanban board that keeps your data on your machine.
+              Create your first board to get started.
+            </p>
+          </div>
+          <div className="flex items-center gap-3">
+            <Button size="lg" onClick={() => setDialogOpen(true)}>
               <Plus className="size-4" />
-              New Board
+              Create Board
             </Button>
             <ImportExportButtons />
           </div>