admin docs: verify object existence, mark dead links, cleaner 404

The DB can record a pdf_minio_path before the object is uploaded (e.g. a
prepared-filing path written for an order whose prep never completed -- Paul
Wilson / Mark Adams MCS-150s). The documents list now HEAD-checks each key and
returns an exists flag; the UI shows 'not generated yet' instead of a dead View
button, and the stream endpoint returns a clean 404 for a missing object.

api/src/routes/admin.ts

@@ -668,7 +668,21 @@ router.get("/api/v1/admin/compliance-orders/:order_number/documents", requireAdm
     const exists = await pool.query("SELECT 1 FROM compliance_orders WHERE order_number = $1", [req.params.order_number]);
     if (exists.rows.length === 0) { res.status(404).json({ error: "Order not found." }); return; }
     const docs = await collectOrderDocuments(req.params.order_number);
-    res.json({ order_number: req.params.order_number, documents: docs });
+    // Verify each object actually exists in storage so the UI can disable dead
+    // links (a key can be recorded in the DB before the object is uploaded, e.g.
+    // a prepared-filing path written for an order whose prep never completed).
+    const checked = await Promise.all(docs.map(async (d) => {
+      let present = false;
+      try {
+        const url = await presignInternal(d.key);
+        if (url) {
+          const head = await fetch(url, { method: "HEAD" });
+          present = head.ok;
+        }
+      } catch { /* treat as missing */ }
+      return { ...d, exists: present };
+    }));
+    res.json({ order_number: req.params.order_number, documents: checked });
   } catch (err) {
     console.error("[admin/compliance-orders/documents] Error:", err);
     res.status(500).json({ error: "Could not list documents." });
@@ -696,6 +710,10 @@ router.get("/api/v1/admin/compliance-orders/:order_number/document", requireAdmi
     if (!url) { res.status(502).json({ error: "Could not generate object URL." }); return; }
 
     const upstream = await fetch(url);
+    if (upstream.status === 404) {
+      res.status(404).json({ error: "Document not found in storage (it may not have been generated yet)." });
+      return;
+    }
     if (!upstream.ok || !upstream.body) {
       res.status(502).json({ error: `Object fetch failed (${upstream.status}).` });
       return;