[auth][api] accept the 20250424.01 client

Version check now answers "current" for a set of builds rather than one:
SUPPORTED_GAME_VERSIONS carries 20230414 and 20250424.01. GAME_VERSION is
unchanged and still what the server reports for itself (presence, rn.ver).

Adds GET /api/versioncheck/islandedversions, always [] — we never island a
build off into its own matchmaking pool.

The 2025 build POSTs /cachedlogin/forplatformid/:platform/:id with a
deviceId/platformAuth/time form body where the 2023 build GETs it, so that
route now takes both methods. The body is accepted and ignored for now.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/api/src/openapi.ts

@@ -145,7 +145,13 @@ export const ApiConfigV2 = JsonObject.describe(
 	'The static client config, plus a ShareBaseUrl templated from the deploy domain'
 )
 
-/** `GET /api/versioncheck/v4` — whether the client's `?v=` build matches GAME_VERSION. */
+/**
+ * `GET /api/versioncheck/islandedversions` — builds islanded onto their own matchmaking
+ * pool. Always empty here.
+ */
+export const IslandedVersions = z.array(z.string())
+
+/** `GET /api/versioncheck/v4` — whether the client's `?v=` build is one we serve. */
 export const VersionCheck = z.object({
 	VersionStatus: z.int().describe('0 = current, 1 = client on a different build'),
 	UpdateNotificationStage: z.int(),

apps/api/src/routes/config.ts

@@ -1,7 +1,7 @@
 import { Hono } from 'hono'
 import { describeRoute } from 'hono-openapi'
 
-import { GAME_VERSION } from '@repo/domain'
+import { isSupportedGameVersion } from '@repo/domain'
 
 import apiConfigV2 from '../../static/api-config-v2.json'
 import gameConfigsV1All from '../../static/gameconfigs-v1-all.json'
@@ -10,6 +10,7 @@ import {
 	ApiConfigV2,
 	AzureSpeechConfig,
 	BacktraceConfig,
+	IslandedVersions,
 	json,
 	JsonObject,
 	VersionCheck,
@@ -100,18 +101,33 @@ export const configRoutes = new Hono<App>({ strict: false })
 			summary: 'Client version check',
 			description:
 				'Whether the client build is current. Compares the client’s `?v=` build against ' +
-				'our target `GAME_VERSION`: `VersionStatus` is 0 when they match, 1 when the ' +
-				'client is on a different build.',
+				'the builds we serve (`SUPPORTED_GAME_VERSIONS`): `VersionStatus` is 0 when the ' +
+				'client is on one of them, 1 when it is on some other build.',
 			responses: { 200: json(VersionCheck, 'Version status') },
 		}),
 		(c) =>
 			c.json({
-				VersionStatus: c.req.query('v') === GAME_VERSION ? 0 : 1,
+				VersionStatus: isSupportedGameVersion(c.req.query('v')) ? 0 : 1,
 				UpdateNotificationStage: 0,
 				IsVersionIslanded: false,
 				IsCrossPlayDisabled: false,
 			})
 	)
+	// Islanding splits players onto version-specific matchmaking pools. We serve every
+	// supported build from one pool, so the list is empty — the client reads it as
+	// "nobody is islanded" and matchmakes normally.
+	.get(
+		'/api/versioncheck/islandedversions',
+		describeRoute({
+			tags: ['Config'],
+			summary: 'Islanded client builds',
+			description:
+				'The builds that are islanded off into their own matchmaking pool. This server ' +
+				'never islands a build, so the list is always empty.',
+			responses: { 200: json(IslandedVersions, 'Always an empty list') },
+		}),
+		(c) => c.json([])
+	)
 	.get(
 		'/api/gameconfigs/v1/all',
 		describeRoute({

apps/api/src/test/integration/api.test.ts

@@ -19,6 +19,7 @@ import {
 	ROOM_SCHEMA_DDL,
 	seedRoomWithSubRooms,
 	SUBROOM_SCHEMA_DDL,
+	SUPPORTED_GAME_VERSIONS,
 } from '@repo/domain'
 
 import '../../api.app'
@@ -197,11 +198,29 @@ describe('public endpoints', () => {
 		expect(await res.json()).toMatchObject({ VersionStatus: 0 })
 	})
 
+	test('GET /api/versioncheck/v4 reports current for every supported build', async () => {
+		for (const version of SUPPORTED_GAME_VERSIONS) {
+			const res = await exports.default.fetch(`${ORIGIN}/api/versioncheck/v4?v=${version}`)
+			expect(await res.json(), version).toMatchObject({ VersionStatus: 0 })
+		}
+	})
+
 	test('GET /api/versioncheck/v4 flags a mismatched build', async () => {
 		const res = await exports.default.fetch(`${ORIGIN}/api/versioncheck/v4?v=19990101`)
 		expect(await res.json()).toMatchObject({ VersionStatus: 1 })
 	})
 
+	test('GET /api/versioncheck/v4 flags a client that sends no build', async () => {
+		const res = await exports.default.fetch(`${ORIGIN}/api/versioncheck/v4`)
+		expect(await res.json()).toMatchObject({ VersionStatus: 1 })
+	})
+
+	test('GET /api/versioncheck/islandedversions is empty', async () => {
+		const res = await exports.default.fetch(`${ORIGIN}/api/versioncheck/islandedversions`)
+		expect(res.status).toBe(200)
+		expect(await res.json()).toEqual([])
+	})
+
 	test('GET /api/relationships/v2/get returns empty array for a player with none', async () => {
 		const res = await exports.default.fetch(`${ORIGIN}/api/relationships/v2/get`, {
 			headers: await bearer('99999'),
@@ -3646,6 +3665,7 @@ describe('openapi', () => {
 			'GET /api/roomkeys/v1/mine',
 			'GET /api/roomkeys/v1/room',
 			'GET /api/rooms/v1/filters',
+			'GET /api/versioncheck/islandedversions',
 			'GET /api/versioncheck/v4',
 			'GET /voice/config',
 			'POST /api/PlayerReporting/v1/deviceId',