feat: registration gravity from DB config instead of hardcoded

- Add registrationGravity to pricing config (default 50, adjustable via admin)
- Inject PricingService into UserService, read config for all 4 registration paths
- Expose registrationGravity in /member/plans response for frontend
- Login page fetches dynamic value from API, replaces hardcoded '50'
- Update user.vue gravity card copy

backend/src/modules/member/member.controller.ts

@@ -53,6 +53,7 @@ export class MemberController {
     }
 
     return {
+      registrationGravity: pricing.registrationGravity,
       interview: { dailyFreeLimit: FREE_DAILY_LIMIT, maxRoundsFree: 5, maxRoundsVip: 10 },
       gravityRates: pricing.gravityRates,
       products: {

backend/src/modules/schemas/pricing.service.ts

@@ -10,6 +10,8 @@ export interface GravityRates {
 }
 
 interface PricingConfig {
+  /** 新用户注册赠送引力值 */
+  registrationGravity: number
   interview: { pricePerSession: number; creditsPerPurchase: number }
   resumeOptimize: { freeLimit: number; pricePerOptimize: number; creditsPerPurchase: number }
   resumeDownload: { pricePerDownload: number; creditsPerPurchase: number }
@@ -21,6 +23,7 @@ interface PricingConfig {
 }
 
 const DEFAULT_PRICING: PricingConfig = {
+  registrationGravity: 50,
   interview: { pricePerSession: 600, creditsPerPurchase: 1 },
   resumeOptimize: { freeLimit: 3, pricePerOptimize: 400, creditsPerPurchase: 1 },
   resumeDownload: { pricePerDownload: 200, creditsPerPurchase: 1 },
@@ -62,6 +65,7 @@ export class PricingService {
 
   private mergeDefaults(value: any): PricingConfig {
     return {
+      registrationGravity: value?.registrationGravity ?? DEFAULT_PRICING.registrationGravity,
       interview: { ...DEFAULT_PRICING.interview, ...value?.interview },
       resumeOptimize: { ...DEFAULT_PRICING.resumeOptimize, ...value?.resumeOptimize },
       resumeDownload: { ...DEFAULT_PRICING.resumeDownload, ...value?.resumeDownload },

backend/src/modules/user/user.service.ts

@@ -5,6 +5,7 @@ import { Model } from 'mongoose'
 import { JwtService } from '@nestjs/jwt'
 import { User, UserDocument } from './user.schema'
 import { EmailService } from '../email/email.service'
+import { PricingService } from '../schemas/pricing.service'
 
 /** 通过 IP 查询粗略地理位置（ip-api.com 免费接口） */
 async function lookupIpLocation(ip: string): Promise<string> {
@@ -30,6 +31,7 @@ export class UserService {
     @InjectModel(User.name) private userModel: Model<UserDocument>,
     private jwtService: JwtService,
     private emailService: EmailService,
+    private pricingService: PricingService,
   ) {}
 
   async sendCode(phone: string) {
@@ -58,7 +60,7 @@ export class UserService {
 
     let user = await this.userModel.findOne({ phone }).exec()
     if (!user) {
-      user = await this.userModel.create({ phone, nickname: `用户${phone.slice(-4)}`, gravity: 5 })
+      user = await this.userModel.create({ phone, nickname: `用户${phone.slice(-4)}`, gravity: (await this.pricingService.getConfig()).registrationGravity })
     }
 
     await this.recordLogin(user._id.toString(), ip)
@@ -94,7 +96,7 @@ export class UserService {
 
     let user = await this.userModel.findOne({ wxOpenid: openid }).exec()
     if (!user) {
-      user = await this.userModel.create({ wxOpenid: openid, nickname: '微信用户', gravity: 5 })
+      user = await this.userModel.create({ wxOpenid: openid, nickname: '微信用户', gravity: (await this.pricingService.getConfig()).registrationGravity })
     }
 
     await this.recordLogin(user._id.toString(), ip)
@@ -170,7 +172,7 @@ export class UserService {
     if (!user) {
       isNew = true
       const nick = email.split('@')[0]
-      user = await this.userModel.create({ email, nickname: nick, remaining: 0, gravity: 5 })
+      user = await this.userModel.create({ email, nickname: nick, remaining: 0, gravity: (await this.pricingService.getConfig()).registrationGravity })
     }
     await this.recordLogin(user._id.toString(), ip)
     return { ...this.generateAuthResponse(user), isNew, hasPassword: !!user.password }
@@ -208,7 +210,7 @@ export class UserService {
     }
     const nick = email.split('@')[0]
     const hashed = await bcrypt.hash(password, 10)
-    const user = await this.userModel.create({ email, nickname: nick, password: hashed, remaining: 0, gravity: 5 })
+    const user = await this.userModel.create({ email, nickname: nick, password: hashed, remaining: 0, gravity: (await this.pricingService.getConfig()).registrationGravity })
     await this.recordLogin(user._id.toString(), ip)
     return this.generateAuthResponse(user)
   }