chore: standardize TypeScript version to 6.0.2 across workspace

- Updated pnpm-workspace.yaml to enforce TypeScript version 6.0.2.
- Replaced legacy TypeScript import with the current version in comparison tools.
- Added ignoreDeprecations setting in tsconfig.base.json to suppress deprecation warnings for baseUrl.
- Introduced TypeScript version policy documentation outlining the rationale and upgrade gate for moving to TypeScript 7.

app/game-frontend/package.json

@@ -40,7 +40,7 @@
         "autoprefixer": "^10.4.23",
         "postcss": "^8.5.6",
         "tailwindcss": "^4.1.18",
-        "typescript": "^5.9.3",
+        "typescript": "6.0.2",
         "vite": "^7.3.1",
         "vue-tsc": "^3.2.2"
     }

app/gateway-frontend/package.json

@@ -33,7 +33,7 @@
         "autoprefixer": "^10.4.23",
         "postcss": "^8.5.6",
         "tailwindcss": "^4.1.18",
-        "typescript": "^5.9.3",
+        "typescript": "6.0.2",
         "vite": "^7.3.0",
         "vue-tsc": "^3.2.1"
     }