Player accounts backend: schema, registration, self-service, SSO provision

- Widen users.role enum to include 'player'; make password_hash nullable;
  add email/email_verified/status/last_login_ip; pin username _ci collation.
- POST /auth/register (honeypot + registerLimiter + botScore, reserved-name
  blocklist, duplicate->409, auto-login). player_registration setting gates it.
- SSO auto-provision in finishLogin (setting-gated); return/portal-aware SSO
  redirects for the player portal; status refusal on login + requireAuth.
- New /player self-service group (account, change username/password, TOTP,
  identities), reusing account.controller; accountChangeLimiter.
- Admin: 'player' role + status/email on user create/update, role/status audit,
  player_registration enum validation, derived public registration flags.
- usernamePolicy module (reserved, sanitize, derive, dedup) + unit tests;
  extend SSO callback tests. 133 server tests green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019rao86n5cXpwAyjdBFEshV

server/src/router/v1/auth/auth.routes.js

@@ -1,10 +1,10 @@
 const express = require('express')
 const { body } = require('express-validator')
 
-const { login, loginTotp, logout, me, HONEYPOT_FIELD } = require('./auth.controller')
+const { login, register, loginTotp, logout, me, HONEYPOT_FIELD } = require('./auth.controller')
 const { isLoggedIn } = require('../../../utils/auth')
 const { attachSession } = require('../../../auth/session.middleware')
-const { loginLimiter } = require('../../../middleware/rateLimit')
+const { loginLimiter, registerLimiter } = require('../../../middleware/rateLimit')
 const { slowLogin, backoffGuard } = require('../../../middleware/loginProtection')
 const validate = require('../../../middleware/validate')
 const mobileRouter = require('./mobile.routes')
@@ -45,6 +45,30 @@ authRouter.post(
   login,
 )
 
+// Public self-registration (player accounts). Gated in the controller by the
+// player_registration setting; here it reuses the login backoff/limiter stack
+// plus its own per-IP cap, and accepts the honeypot field.
+authRouter.post(
+  '/register',
+  // #swagger.tags = ['Auth']
+  // #swagger.summary = 'Register a player account'
+  // #swagger.description = 'Creates a self-service player account and logs it in (sets the session cookie). Available only when an admin has enabled password registration (player_registration = password|both); otherwise returns 403. Rate limited and behind bot/backoff guards; a hidden honeypot field must stay empty.'
+  /* #swagger.requestBody = { required: true, content: { "application/json": { schema: { $ref: "#/components/schemas/RegisterRequest" } } } } */
+  /* #swagger.responses[200] = { description: 'Account created and session issued', content: { "application/json": { schema: { $ref: "#/components/schemas/LoginResponse" } } } } */
+  /* #swagger.responses[400] = { description: 'Validation error or unavailable username', content: { "application/json": { schema: { $ref: "#/components/schemas/ValidationError" } } } } */
+  /* #swagger.responses[403] = { description: 'Registration is not open', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
+  /* #swagger.responses[409] = { description: 'Username already taken', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
+  /* #swagger.responses[429] = { description: 'Too many attempts (rate limited / backoff)', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
+  ...loginGuards,
+  registerLimiter,
+  body('username').isString().trim().isLength({ min: 3, max: 32 }),
+  body('password').isString().isLength({ min: 8, max: 64 }),
+  body('email').optional({ values: 'falsy' }).isEmail().isLength({ max: 255 }),
+  body(HONEYPOT_FIELD).optional(),
+  validate,
+  register,
+)
+
 // Second factor: same throttling, since it's a code-guessing surface too.
 authRouter.post(
   '/login/totp',