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.

tsconfig.base.json

@@ -8,6 +8,7 @@
         "esModuleInterop": true,
         "forceConsistentCasingInFileNames": true,
         "skipLibCheck": true,
+        "ignoreDeprecations": "6.0",
         "declaration": true,
         "declarationMap": true,
         "sourceMap": true