Add packages/common for shared utilities

Create new @reviq/common package with environment-agnostic utilities:
- Date formatting: formatDate, formatDateTime, formatLongDate,
  formatRelativeDate, formatRelativeTime
- User utilities: getUserInitials, formatRole

Consolidate date formatting from publisher-dashboard into shared package.
All utilities include comprehensive test coverage with bun:test.

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

packages/common/eslint.config.js

@@ -0,0 +1,15 @@
+import { configs } from "@macalinao/eslint-config";
+
+export default [
+  ...configs.fast,
+  {
+    ignores: ["**/*.test.ts"],
+  },
+  {
+    languageOptions: {
+      parserOptions: {
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+  },
+];