fix(auth): harden refresh ownership and scheduler after auth migration

Restore /health to { ok: true }. Scope refresh to owned devices via
deviceId/fcmToken, improve register upsert logging, skip legacy rows in
the scheduler with per-token dedupe, and prefer non-legacy rows for push.

src/db/fcmTokens.ts

@@ -206,6 +206,44 @@ export const db = {
     return Object.values(all);
   },
 
+  /** Scheduler iteration; excludes legacy rows pending migration cleanup. */
+  async getAllForScheduler(): Promise<StoredRow[]> {
+    const all = await load();
+    // TODO: migrate or remove __legacy__ rows after auth rollout
+    return Object.values(all).filter((r) => r.userId !== "__legacy__");
+  },
+
+  /**
+   * Resolve a device owned by userId via deviceId and/or fcmToken.
+   * When both are given, they must refer to the same row.
+   */
+  async resolveOwnedDevice(
+    userId: string,
+    query: { deviceId?: string; fcmToken?: string }
+  ): Promise<StoredRow | undefined> {
+    const deviceId = query.deviceId?.trim();
+    const fcmToken = query.fcmToken;
+
+    if (deviceId !== undefined && deviceId.length > 0) {
+      const byDevice = await this.getByDeviceId(userId, deviceId);
+      if (byDevice === undefined) return undefined;
+      if (
+        fcmToken !== undefined &&
+        fcmToken.length > 0 &&
+        byDevice.fcmToken !== fcmToken
+      ) {
+        return undefined;
+      }
+      return byDevice;
+    }
+
+    if (fcmToken !== undefined && fcmToken.length > 0) {
+      return this.getByFcmTokenForUser(userId, fcmToken);
+    }
+
+    return undefined;
+  },
+
   async getByUserId(userId: string): Promise<StoredRow[]> {
     const all = await load();
     return Object.values(all).filter((r) => r.userId === userId);
@@ -221,7 +259,14 @@ export const db = {
 
   async getByFcmToken(fcmToken: string): Promise<StoredRow | undefined> {
     const all = await load();
-    return Object.values(all).find((r) => r.fcmToken === fcmToken);
+    const matches = Object.values(all).filter((r) => r.fcmToken === fcmToken);
+    if (matches.length === 0) return undefined;
+    const owned = matches.filter((r) => r.userId !== "__legacy__");
+    const pool = owned.length > 0 ? owned : matches;
+    return pool.sort(
+      (a, b) =>
+        new Date(b.updatedAt).getTime() - new Date(a.updatedAt).getTime()
+    )[0];
   },
 
   async getByFcmTokenForUser(

src/index.ts

@@ -9,8 +9,9 @@ const port = Number(process.env.PORT) || 3000;
 
 app.use(express.json());
 
+// Keep stable for diagnostics tooling compatibility
 app.get("/health", (_req, res) => {
-  res.status(200).json({ status: "ok" });
+  res.status(200).json({ ok: true });
 });
 
 app.use("/notifications", notificationsRouter);

src/routes/notifications.ts

@@ -1,6 +1,7 @@
 import { Router } from "express";
 import { db } from "../db/fcmTokens.js";
 import { requireAuth } from "../middleware/auth.js";
+import { maskToken } from "../util/maskToken.js";
 
 export const notificationsRouter = Router();
 
@@ -15,11 +16,46 @@ notificationsRouter.post("/refresh", requireAuth, async (req, res) => {
     return;
   }
 
-  const devices = await db.getByUserId(userId);
+  const { deviceId, fcmToken } = req.body as {
+    deviceId?: unknown;
+    fcmToken?: unknown;
+  };
+
+  const canonicalDeviceId =
+    typeof deviceId === "string" ? deviceId.trim() : undefined;
+  const token =
+    typeof fcmToken === "string" && fcmToken.length > 0 ? fcmToken : undefined;
+
+  if (
+    (canonicalDeviceId === undefined || canonicalDeviceId.length === 0) &&
+    token === undefined
+  ) {
+    res.status(400).json({ error: "deviceId or fcmToken is required" });
+    return;
+  }
+
+  const device = await db.resolveOwnedDevice(userId, {
+    deviceId: canonicalDeviceId,
+    fcmToken: token,
+  });
+
+  if (device === undefined) {
+    console.log(
+      "[Refresh] Device lookup failed for user:",
+      userId,
+      canonicalDeviceId !== undefined
+        ? `deviceId=${canonicalDeviceId}`
+        : "",
+      token !== undefined ? `token suffix=${maskToken(token)}` : ""
+    );
+    res.status(404).json({ error: "Device not found" });
+    return;
+  }
+
   console.log(
-    "[Refresh] authenticated refresh request:",
-    userId,
-    `(${devices.length} device(s))`
+    "[Refresh] Device ownership validated:",
+    device.deviceId,
+    maskToken(device.fcmToken)
   );
   const now = Date.now();
 
@@ -70,11 +106,23 @@ notificationsRouter.post("/register", requireAuth, async (req, res) => {
   const canonicalDeviceId = deviceId.trim();
 
   try {
-    console.log("[Register] user authenticated:", userId);
     const existing = await db.getByDeviceId(userId, canonicalDeviceId);
-    console.log("[Register] Upserting device:", canonicalDeviceId);
-    if (existing !== undefined && existing.fcmToken !== fcmToken) {
-      console.log("[Register] Replacing token for device:", canonicalDeviceId);
+    if (existing !== undefined) {
+      if (existing.fcmToken !== fcmToken) {
+        console.log(
+          "[Register] Updating existing device token:",
+          canonicalDeviceId,
+          maskToken(fcmToken)
+        );
+      } else {
+        console.log("[Register] Updating existing device:", canonicalDeviceId);
+      }
+    } else {
+      console.log(
+        "[Register] Creating new device registration:",
+        canonicalDeviceId,
+        maskToken(fcmToken)
+      );
     }
 
     await db.upsert({

src/scheduler.ts

@@ -1,5 +1,6 @@
 import { db } from "./db/fcmTokens.js";
 import { sendPushToDevice } from "./services/pushService.js";
+import { maskToken } from "./util/maskToken.js";
 
 let intervalId: ReturnType<typeof setInterval> | undefined;
 
@@ -9,8 +10,19 @@ export function startScheduler(): void {
   intervalId = setInterval(async () => {
     try {
       console.log("[Scheduler] Checking devices...");
-      const devices = await db.getAll();
+      const devices = await db.getAllForScheduler();
+      const seenTokens = new Set<string>();
+
       for (const d of devices) {
+        if (seenTokens.has(d.fcmToken)) {
+          console.log(
+            "[Scheduler] Duplicate device skipped:",
+            d.deviceId,
+            maskToken(d.fcmToken)
+          );
+          continue;
+        }
+        seenTokens.add(d.fcmToken);
         await sendPushToDevice(d.fcmToken);
       }
     } catch (err) {