Rename @reviq/utils to @reviq/server-utils and add package READMEs

- Rename packages/utils/ to packages/server-utils/
- Update all imports and package.json references
- Add READMEs for frontend-utils, server-utils, and common packages
- Update main README with new package structure

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

packages/server-utils/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "extends": "@macalinao/tsconfig/tsconfig.base.json",
+  "compilerOptions": {
+    "types": ["bun"]
+  }
+}