refactor(server): split public, player and residual auth into capability routers (PR 5)

The last split PR of docs/website/API_V2_PLAN.md § Phase 2. public.routes.js,
player.routes.js and auth.routes.js are deleted; each group is now a directory
whose index.js owns the group gate and the mount table and declares no routes.
Every one of the 200 manifest routes is now in a capability router.

  public/  posts (2) wiki (4) pages (2) shard (12) site (4, group root)
  player/  account (8) shard (8) appeals (4), behind noindex + requireAuth
  auth/    login (2) register (1) invite (2) password (3) session (2, root)

No URL moves. All four gates zero-diff: routes.manifest.json (200 public + 2
internal), routes.guards.json, swagger-output.json (198 operations), and
docs/website/api-route-inventory.json was already in sync. 434 tests green.

Notes on the non-mechanical parts:

- public/index.js and auth/index.js carry no group gate, deliberately, and say
  so. The public surface is anonymous by contract (logged-out SPA, Discord bot,
  Android ShardStreamClient on /public/shard/stream); /auth is where a caller
  becomes authenticated. player/index.js gates on requireAuth only, never
  requireRole('player') — staff are a superset of players.
- GET /auth/me has a mount-order dependency: use('/me', meRouter) matches the
  bare /me, so the request runs meRouter's noindex + requireAuth and falls
  through. session.router.js must stay mounted last. Verified by the
  counterfactual — mounting it first still 401s but drops X-Robots-Tag, which
  no manifest or guards file can see.
- loginGuards moved to auth/loginGuards.js (frozen) rather than being copied
  into the three routers that spread it; sso.routes.js drops its duplicate.
- The :param shadowing check was re-run in dispatch order against the built
  stack: 86 routes, 64 literal, none shadowed. /public/wiki/{categories,tags}
  ahead of /:slug is the only ordering-sensitive pair.

Co-Authored-By: Claude <noreply@anthropic.com>

server/src/router/v1/public/site.router.js

@@ -0,0 +1,67 @@
+// Public · Site — the four group-root singletons: settings, status, version and
+// contact. None of them owns a path segment that could become a prefix, so this
+// is the public group's counterpart to admin/dashboard.router.js: one file for
+// the routes that own no prefix, mounted at the group root.
+//
+// It is safe at the root **only** because this file declares no router-level
+// middleware. A bare `use(gate)` in a root-mounted router runs for every request
+// passing through toward another mount — it would gate /public/wiki and
+// /public/shard/* too. Keep gates on the individual routes here (siteMode is
+// deliberately absent: settings/status/version/contact must answer during
+// maintenance so the client can render the maintenance page and let a visitor
+// get in touch).
+//
+// Mounted at /api/v1/public by public/index.js.
+
+const express = require('express')
+const { body } = require('express-validator')
+
+const ctrl = require('./public.controller')
+const validate = require('../../../middleware/validate')
+const { contactLimiter } = require('../../../middleware/rateLimit')
+
+const siteRouter = express.Router()
+
+siteRouter.get(
+  '/settings',
+  // #swagger.tags = ['Public']
+  // #swagger.summary = 'Public site settings + branding'
+  // #swagger.description = 'Whitelisted, non-sensitive settings plus the per-shard brand block (name/colors/logo/hero/favicon) a client themes itself from, and derived registration / game-account-signup availability flags.'
+  /* #swagger.responses[200] = { description: 'Public settings + branding', content: { "application/json": { schema: { $ref: "#/components/schemas/PublicSettings" } } } } */
+  ctrl.getSettings,
+)
+siteRouter.get(
+  '/status',
+  // #swagger.tags = ['Public']
+  // #swagger.summary = 'Site mode / status'
+  // #swagger.description = 'Current site mode (live or maintenance) so the client can show the maintenance page, plus a version block (service id + API/server versions) for a client first-run probe and version-mismatch guard.'
+  /* #swagger.responses[200] = { description: 'Site status', content: { "application/json": { schema: { $ref: "#/components/schemas/PublicStatus" } } } } */
+  ctrl.getStatus,
+)
+siteRouter.get(
+  '/version',
+  // #swagger.tags = ['Public']
+  // #swagger.summary = 'Backend identity + version'
+  // #swagger.description = 'Lightweight, DB-free descriptor of this backend: a stable service id and the API/server versions. A client uses it to recognize a Runic Gateway backend on first-run and to run a version-mismatch guard. Doubles as a cheap liveness check.'
+  /* #swagger.responses[200] = { description: 'Backend version', content: { "application/json": { schema: { $ref: "#/components/schemas/PublicVersion" } } } } */
+  ctrl.getVersion,
+)
+siteRouter.post(
+  '/contact',
+  // #swagger.tags = ['Public']
+  // #swagger.summary = 'Send a contact message'
+  // #swagger.description = 'Emails the site owner (or falls back to a mailto). Rate limited.'
+  /* #swagger.requestBody = { required: true, content: { "application/json": { schema: { $ref: "#/components/schemas/ContactRequest" } } } } */
+  /* #swagger.responses[200] = { description: 'Message sent', content: { "application/json": { schema: { $ref: "#/components/schemas/Message" } } } } */
+  /* #swagger.responses[400] = { description: 'Validation error', content: { "application/json": { schema: { $ref: "#/components/schemas/ValidationError" } } } } */
+  /* #swagger.responses[429] = { description: 'Too many messages (rate limited)', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
+  /* #swagger.responses[502] = { description: 'Mail delivery failed', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
+  contactLimiter,
+  body('message').isString().trim().notEmpty().isLength({ max: 5000 }),
+  body('email').optional({ values: 'falsy' }).isEmail(),
+  body('name').optional({ values: 'falsy' }).isString().trim().isLength({ max: 100 }),
+  validate,
+  ctrl.contact,
+)
+
+module.exports = siteRouter