feat: add inline PDF viewer for Custom_PDF objects

Add a /pdf proxy route that forces Content-Disposition inline so PDFs render instead of downloading, and a web viewer that embeds the document in an iframe with a standalone open-in-new-tab link.

apps/web/src/components/viewers/PdfViewer.tsx

@@ -0,0 +1,43 @@
+import type { TTSObject } from '@tts/shared';
+import { pdfUrl } from '@tts/http';
+
+/**
+ * A PDF document (`Custom_PDF`). Renders the document inline in an iframe and
+ * offers a standalone link to open it in a new tab. The URL is routed through
+ * the proxy `/pdf` endpoint, which forces `Content-Disposition: inline` so the
+ * browser displays the PDF instead of downloading it.
+ */
+export default function PdfViewer({ object }: { object: TTSObject }) {
+  const url = object.CustomPDF?.PDFUrl;
+
+  if (!url) {
+    return (
+      <p className="text-sm text-zinc-500">
+        This object has no PDF URL.
+      </p>
+    );
+  }
+
+  const proxied = pdfUrl(url);
+
+  return (
+    <div className="space-y-3">
+      <div className="flex items-center justify-between gap-2">
+        <p className="truncate font-mono text-xs text-zinc-500">{url}</p>
+        <a
+          href={proxied}
+          target="_blank"
+          rel="noreferrer"
+          className="shrink-0 rounded-lg bg-zinc-100 px-3 py-1.5 text-sm font-medium text-zinc-900 hover:bg-zinc-300"
+        >
+          Open PDF in new tab
+        </a>
+      </div>
+      <iframe
+        src={proxied}
+        title="PDF preview"
+        className="h-[70vh] w-full rounded-lg border border-zinc-800 bg-zinc-950"
+      />
+    </div>
+  );
+}

apps/web/src/components/viewers/register.ts

@@ -9,6 +9,7 @@ const TileViewer = lazy(() => import('./TileViewer'));
 const TokenViewer = lazy(() => import('./TokenViewer'));
 const CardViewer = lazy(() => import('./CardViewer'));
 const CustomModelViewer = lazy(() => import('./CustomModelViewer'));
+const PdfViewer = lazy(() => import('./PdfViewer'));
 
 registerViewer('Tile', TileViewer);
 registerViewer('Custom_Tile', TileViewer);
@@ -20,4 +21,5 @@ registerViewer('DeckCustom', CardViewer);
 registerViewer('Custom_Deck', CardViewer);
 registerViewer('Custom_Model', CustomModelViewer);
 registerViewer('Custom_Model_Bag', CustomModelViewer);
-registerViewer('Custom_Model_Infinite_Bag', CustomModelViewer);
+registerViewer('Custom_Model_Infinite_Bag', CustomModelViewer);
+registerViewer('Custom_PDF', PdfViewer);