fix(server): lazy-load game validators to avoid ES module errors

Problem:
- Production server failing at startup with "Cannot find name 'scaleX'" and ES module errors
- @svg-maps/world ES module being imported in CommonJS context
- server.js uses require() which can't handle ES modules

Root cause:
- validators.ts imported all validators at module load time
- know-your-world validator imports maps.ts
- maps.ts imports @svg-maps/world (ES module)
- When server.js requires validators.ts, it fails

Solution:
- Convert validators.ts to use lazy loading with dynamic imports
- Validators are now loaded on-demand when first requested
- Cached after first load for performance
- This avoids importing ES modules until actually needed

Changes:
- validators.ts: Replace static imports with lazy loaders
- validators.ts: Make getValidator() async, returns Promise<GameValidator>
- session-manager.ts: Add await to getValidator() calls
- socket-server.ts: Add await to getValidator() calls
- validation/index.ts: Remove re-exports of validator instances
- game-registry.ts: Remove validator comparison (can't sync compare async)

Impact:
- Server.js can now start without ES module errors
- Next.js build still works (handles ES modules natively)
- Small performance hit on first validator access (cached thereafter)
- Breaking change: getValidator() is now async

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/.claude/settings.local.json

@@ -52,11 +52,18 @@
       "Bash(npm install:*)",
       "Bash(pnpm add:*)",
       "Bash(node -e:*)",
-      "Bash(npm search:*)"
+      "Bash(npm search:*)",
+      "Bash(git revert:*)",
+      "Bash(pnpm remove:*)",
+      "Bash(gh run view:*)",
+      "Bash(pnpm install:*)",
+      "Bash(git checkout:*)"
     ],
     "deny": [],
     "ask": []
   },
   "enableAllProjectMcpServers": true,
-  "enabledMcpjsonServers": ["sqlite"]
+  "enabledMcpjsonServers": [
+    "sqlite"
+  ]
 }

apps/web/src/lib/arcade/session-manager.ts

@@ -202,7 +202,7 @@ export async function applyGameMove(
   }
 
   // Get the validator for this game
-  const validator = getValidator(session.currentGame as GameName)
+  const validator = await getValidator(session.currentGame as GameName)
 
   // Fetch player ownership for authorization checks (room-based games)
   let playerOwnership: PlayerOwnershipMap | undefined

apps/web/src/lib/arcade/validation/index.ts

@@ -4,16 +4,8 @@
  * New code should import from '@/lib/arcade/validators' instead
  */
 
-// Re-export everything from unified registry
-export {
-  getValidator,
-  hasValidator,
-  getRegisteredGameNames,
-  validatorRegistry,
-  matchingGameValidator,
-  memoryQuizGameValidator,
-  cardSortingValidator,
-} from '../validators'
+// Re-export core functions and types from unified registry
+export { getValidator, hasValidator, getRegisteredGameNames } from '../validators'
 
 export type { GameName } from '../validators'
 export * from './types'

apps/web/src/lib/arcade/validators.ts

@@ -4,55 +4,70 @@
  * This is the single source of truth for game validators.
  * Both client and server import validators from here.
  *
+ * IMPORTANT: Uses lazy loading to avoid importing ES modules at module load time.
+ * This allows the registry to be loaded on the server without causing ES module errors.
+ *
  * To add a new game:
- * 1. Import the validator
- * 2. Add to validatorRegistry Map
+ * 1. Add the lazy loader function
+ * 2. Add to validatorLoaders Map
  * 3. GameName type will auto-update
  */
 
-import { matchingGameValidator } from '@/arcade-games/matching/Validator'
-import { memoryQuizGameValidator } from '@/arcade-games/memory-quiz/Validator'
-import { complementRaceValidator } from '@/arcade-games/complement-race/Validator'
-import { cardSortingValidator } from '@/arcade-games/card-sorting/Validator'
-import { yjsDemoValidator } from '@/arcade-games/yjs-demo/Validator'
-import { rithmomachiaValidator } from '@/arcade-games/rithmomachia/Validator'
-import { knowYourWorldValidator } from '@/arcade-games/know-your-world/Validator'
 import type { GameValidator } from './validation/types'
 
 /**
- * Central registry of all game validators
- * Key: game name (matches manifest.name)
- * Value: validator instance
+ * Lazy validator loaders - import validators only when needed
  */
-export const validatorRegistry = {
-  matching: matchingGameValidator,
-  'memory-quiz': memoryQuizGameValidator,
-  'complement-race': complementRaceValidator,
-  'card-sorting': cardSortingValidator,
-  'yjs-demo': yjsDemoValidator,
-  rithmomachia: rithmomachiaValidator,
-  'know-your-world': knowYourWorldValidator,
+const validatorLoaders = {
+  matching: async () => (await import('@/arcade-games/matching/Validator')).matchingGameValidator,
+  'memory-quiz': async () =>
+    (await import('@/arcade-games/memory-quiz/Validator')).memoryQuizGameValidator,
+  'complement-race': async () =>
+    (await import('@/arcade-games/complement-race/Validator')).complementRaceValidator,
+  'card-sorting': async () =>
+    (await import('@/arcade-games/card-sorting/Validator')).cardSortingValidator,
+  'yjs-demo': async () => (await import('@/arcade-games/yjs-demo/Validator')).yjsDemoValidator,
+  rithmomachia: async () =>
+    (await import('@/arcade-games/rithmomachia/Validator')).rithmomachiaValidator,
+  'know-your-world': async () =>
+    (await import('@/arcade-games/know-your-world/Validator')).knowYourWorldValidator,
   // Add new games here - GameName type will auto-update
 } as const
 
+/**
+ * Cache for loaded validators
+ */
+const validatorCache = new Map<GameName, GameValidator>()
+
 /**
  * Auto-derived game name type from registry
  * No need to manually update this!
  */
-export type GameName = keyof typeof validatorRegistry
+export type GameName = keyof typeof validatorLoaders
 
 /**
- * Get validator for a game
+ * Get validator for a game (async - lazy loads validator)
  * @throws Error if game not found (fail fast)
  */
-export function getValidator(gameName: string): GameValidator {
-  const validator = validatorRegistry[gameName as GameName]
-  if (!validator) {
+export async function getValidator(gameName: string): Promise<GameValidator> {
+  const gameNameTyped = gameName as GameName
+
+  // Check cache first
+  if (validatorCache.has(gameNameTyped)) {
+    return validatorCache.get(gameNameTyped)!
+  }
+
+  const loader = validatorLoaders[gameNameTyped]
+  if (!loader) {
     throw new Error(
       `No validator found for game: ${gameName}. ` +
-        `Available games: ${Object.keys(validatorRegistry).join(', ')}`
+        `Available games: ${Object.keys(validatorLoaders).join(', ')}`
     )
   }
+
+  // Load and cache
+  const validator = await loader()
+  validatorCache.set(gameNameTyped, validator)
   return validator
 }
 
@@ -60,14 +75,14 @@ export function getValidator(gameName: string): GameValidator {
  * Check if a game has a registered validator
  */
 export function hasValidator(gameName: string): gameName is GameName {
-  return gameName in validatorRegistry
+  return gameName in validatorLoaders
 }
 
 /**
  * Get all registered game names
  */
 export function getRegisteredGameNames(): GameName[] {
-  return Object.keys(validatorRegistry) as GameName[]
+  return Object.keys(validatorLoaders) as GameName[]
 }
 
 /**
@@ -94,16 +109,3 @@ export function assertValidGameName(gameName: unknown): asserts gameName is Game
     )
   }
 }
-
-/**
- * Re-export validators for backwards compatibility
- */
-export {
-  matchingGameValidator,
-  memoryQuizGameValidator,
-  complementRaceValidator,
-  cardSortingValidator,
-  yjsDemoValidator,
-  rithmomachiaValidator,
-  knowYourWorldValidator,
-}

apps/web/src/socket-server.ts

@@ -361,7 +361,7 @@ export function initializeSocketServer(httpServer: HTTPServer) {
               const roomPlayerIds = await getRoomPlayerIds(roomId)
 
               // Get initial state from the correct validator based on game type
-              const validator = getValidator(room.gameName as GameName)
+              const validator = await getValidator(room.gameName as GameName)
 
               // Get game-specific config from database (type-safe)
               const gameConfig = await getGameConfig(roomId, room.gameName as GameName)
@@ -418,7 +418,7 @@ export function initializeSocketServer(httpServer: HTTPServer) {
             }
 
             // Get initial state from validator (this code path is matching-game specific)
-            const matchingValidator = getValidator('matching')
+            const matchingValidator = await getValidator('matching')
             const initialState = matchingValidator.getInitialState({
               difficulty: 6,
               gameType: 'abacus-numeral',