Cleanup: extract constants, fix typecheck, add ESLint, organize store types

- Remove unused initCount state from useAuthGate hook
- Replace magic number with MAX_SAVES_PER_USER constant in saves route
- Extract duplicated EMAIL_REGEX and MIN_PASSWORD_LENGTH in auth routes
- Fix game-simulation typecheck failure by adding DOM lib to tsconfig
- Extract store UI types (ActivePage, InfraNav, etc.) to store/types.ts
- Fix let→const for non-reassigned arrays in servingPipeline
- Fix useless initial assignments in reputationSystem
- Fix ambiguous multiline array access in sanityChecks
- Add minimal ESLint config with typescript-eslint
- Add .planning/ and *.log to .gitignore

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/game-simulation/tsconfig.json

@@ -1,6 +1,7 @@
 {
   "extends": "@token-empire/tsconfig/node.json",
   "compilerOptions": {
+    "lib": ["ES2022", "DOM"],
     "outDir": "dist",
     "rootDir": "src"
   },