refactor: Centralize ESM config in tsconfig.base.json

Move ESM module configuration from individual package tsconfigs to the
shared base configuration for better maintainability.

Changes:
- Updated libs/tsconfig.base.json:
  - Changed module: "commonjs" → "NodeNext"
  - Changed moduleResolution: "node" → "NodeNext"

- Cleaned up all lib package tsconfigs:
  - Removed duplicate module/moduleResolution settings
  - Now all packages inherit ESM config from base
  - Packages: dependency-resolver, git-utils, model-resolver, platform, utils

Benefits:
✅ Single source of truth for module configuration
✅ Less duplication, easier maintenance
✅ Consistent ESM behavior across all lib packages
✅ Simpler package-specific tsconfig files

All packages build successfully. All 632 tests passing.

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

libs/git-utils/tsconfig.json

@@ -2,9 +2,7 @@
   "extends": "../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "./dist",
-    "rootDir": "./src",
-    "module": "NodeNext",
-    "moduleResolution": "NodeNext"
+    "rootDir": "./src"
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules", "dist"]