feat: add getDirectConversations to notifications storage

Groups ap_notifications with isDirect:true by peer actor and returns
them as conversation objects shaped for the DM reader tab template.

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

lib/storage/notifications.js

@@ -195,3 +195,62 @@ export async function deleteNotification(collections, uid) {
   const { ap_notifications } = collections;
   return await ap_notifications.deleteOne({ uid });
 }
+
+/**
+ * Get direct message conversations grouped by peer actor.
+ * Returns conversations sorted by most-recent message, newest first.
+ * @param {object} collections - MongoDB collections
+ * @returns {Promise<Array>} Array of conversation objects
+ */
+export async function getDirectConversations(collections) {
+  const { ap_notifications } = collections;
+
+  const rawItems = await ap_notifications
+    .find({ isDirect: true })
+    .sort({ published: -1 })
+    .limit(200)
+    .toArray();
+
+  // Group by peer (senderActorUrl or actorUrl)
+  const byPeer = new Map();
+  for (const item of rawItems) {
+    const peerUrl = item.senderActorUrl || item.actorUrl || "";
+    if (!peerUrl) continue;
+    if (!byPeer.has(peerUrl)) {
+      byPeer.set(peerUrl, {
+        peerUrl,
+        peerName: item.actorName || "",
+        peerHandle: item.actorHandle || "",
+        peerPhoto: item.actorPhoto || "",
+        hasUnread: false,
+        messages: [],
+      });
+    }
+    const conv = byPeer.get(peerUrl);
+    if (!item.read) conv.hasUnread = true;
+    conv.messages.push({
+      direction: "inbound",
+      url: item.url || "",
+      content: item.content || {},
+      published:
+        item.published instanceof Date
+          ? item.published.toISOString()
+          : item.published || "",
+    });
+  }
+
+  // Each conversation's messages arrived newest-first; reverse to chrono order
+  const conversations = [...byPeer.values()];
+  for (const conv of conversations) {
+    conv.messages.reverse();
+  }
+
+  // Sort conversations by most-recent message (newest first)
+  conversations.sort((a, b) => {
+    const aLast = a.messages.at(-1)?.published || "";
+    const bLast = b.messages.at(-1)?.published || "";
+    return bLast < aLast ? -1 : bLast > aLast ? 1 : 0;
+  });
+
+  return conversations;
+}