Add notification nav, show only replies in short format

static/db.js

@@ -433,6 +433,31 @@ export async function getRepliesForPost(postID) {
     }
     return replies;
 }
+export async function getNotificationsForUser(userID) {
+    const userPostIds = new Set(await getAllIds(userID));
+    const knownUsers = [...(await indexedDB.databases())]
+        .map(db => db.name?.replace('user_', '')).filter(Boolean);
+    let notifications = [];
+    for (const dbUserID of knownUsers) {
+        try {
+            const { store } = await getDBTransactionStore(dbUserID);
+            const index = store.index("postReplyIndex");
+            const results = await new Promise((resolve, reject) => {
+                const req = index.getAll();
+                req.onsuccess = () => resolve(req.result);
+                req.onerror = () => reject(req.error);
+            });
+            for (const r of results) {
+                if (r.data.reply_to_id && userPostIds.has(r.data.reply_to_id)) {
+                    notifications.push(r);
+                }
+            }
+        }
+        catch (_) { }
+    }
+    notifications.sort((a, b) => new Date(b.data.post_timestamp).getTime() - new Date(a.data.post_timestamp).getTime());
+    return notifications;
+}
 export async function getPostsByIds(userID, postIDs) {
     const { store } = await getDBTransactionStore(userID);
     const index = store.index("postIDIndex");