fix: Mongoose 8 pre-save hook crash (next->async), v1.0.17 tag, test user

- user.schema.ts: convert pre-save from callback(next) to async - fixes
  'TypeError: next is not a function' on login (Mongoose 8 compat)
- Tag v1.0.17 for 1.0.18 build cycle
- scripts/seed-test-user.ts: utility to create test accounts
- docs: PROJECT-STATUS v4.9, AGENTS.md version bump
- Add test user test@yzrcloud.cn / 123456 (role: user)

backend/scripts/seed-test-user.ts

@@ -0,0 +1,55 @@
+import { connect, disconnect } from 'mongoose'
+import * as bcrypt from 'bcrypt'
+import * as dotenv from 'dotenv'
+import * as path from 'path'
+
+dotenv.config({ path: path.resolve(__dirname, '../.env') })
+
+async function main() {
+  const uri = process.env.MONGODB_URI
+  if (!uri) {
+    console.error('MONGODB_URI not set')
+    process.exit(1)
+  }
+
+  const conn = await connect(uri)
+  console.log('Connected to MongoDB')
+
+  const users = conn.connection.db!.collection('users')
+
+  const email = 'test@yzrcloud.cn'
+  const password = '123456'
+  const hashed = await bcrypt.hash(password, 10)
+
+  const existing = await users.findOne({ email })
+  if (existing) {
+    await users.updateOne(
+      { email },
+      { $set: { password: hashed, nickname: '测试用户', role: 'user', gravity: 5, interviewCredits: 1, remaining: 3 } }
+    )
+    console.log(`Updated test user: ${email}`)
+  } else {
+    await users.insertOne({
+      email,
+      password: hashed,
+      nickname: '测试用户',
+      role: 'user',
+      gravity: 5,
+      interviewCredits: 1,
+      remaining: 3,
+      interviewCount: 0,
+      plan: 'free',
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    })
+    console.log(`Created test user: ${email}`)
+  }
+
+  await disconnect()
+  console.log('Done')
+}
+
+main().catch(err => {
+  console.error('Failed:', err)
+  process.exit(1)
+})