feat: add passkey-style online profiles for cross-device sync and show build time in About

server/db.js

@@ -53,9 +53,55 @@ export async function initDb() {
 
     CREATE INDEX IF NOT EXISTS idx_vh_fp_time
       ON video_history (fingerprint, accessed_at DESC);
+
+    CREATE TABLE IF NOT EXISTS profiles (
+      name       TEXT    PRIMARY KEY,
+      data       TEXT    NOT NULL DEFAULT '{}',
+      created_at INTEGER NOT NULL DEFAULT (unixepoch()),
+      updated_at INTEGER NOT NULL DEFAULT (unixepoch())
+    );
   `);
 }
 
+// ---- Profiles (named cross-device sync; the name acts as the passkey) ------
+
+// Insert a new profile. Returns false when the name is already taken.
+export async function createProfile(name, dataJson) {
+  try {
+    await db.execute({
+      sql: `INSERT INTO profiles (name, data, created_at, updated_at)
+            VALUES (?, ?, unixepoch(), unixepoch())`,
+      args: [name, dataJson],
+    });
+    return true;
+  } catch (err) {
+    const msg = String(err && err.message || err);
+    if (msg.includes('UNIQUE') || msg.includes('PRIMARY KEY')) return false;
+    throw err;
+  }
+}
+
+export async function getProfile(name) {
+  const r = await db.execute({
+    sql: 'SELECT data, updated_at FROM profiles WHERE name = ?',
+    args: [name],
+  });
+  const row = r.rows[0];
+  if (!row) return null;
+  return { data: row.data, updatedAt: Number(row.updated_at) };
+}
+
+// Update an EXISTING profile's data blob. Returns false when it doesn't exist
+// (saving must never implicitly create a profile — creation is a deliberate,
+// uniqueness-checked act).
+export async function saveProfile(name, dataJson) {
+  const r = await db.execute({
+    sql: 'UPDATE profiles SET data = ?, updated_at = unixepoch() WHERE name = ?',
+    args: [dataJson, name],
+  });
+  return (r.rowsAffected || 0) > 0;
+}
+
 // ---- Helpers ---------------------------------------------------------------
 
 // Upsert the users row and optionally update playlists.