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>

bun.lock

@@ -77,6 +77,7 @@
         "@orpc/client": "^1.13.2",
         "@orpc/contract": "^1.13.2",
         "@reviq/api-contract": "workspace:*",
+        "@reviq/common": "workspace:*",
         "@simplewebauthn/browser": "^13.2.2",
         "@tanstack/svelte-query": "^6.0.14",
         "@tanstack/svelte-query-devtools": "^6.0.3",
@@ -129,6 +130,17 @@
         "typescript": "catalog:",
       },
     },
+    "packages/common": {
+      "name": "@reviq/common",
+      "version": "0.0.1",
+      "devDependencies": {
+        "@macalinao/eslint-config": "catalog:",
+        "@macalinao/tsconfig": "catalog:",
+        "@types/bun": "catalog:",
+        "eslint": "catalog:",
+        "typescript": "catalog:",
+      },
+    },
     "packages/db": {
       "name": "@reviq/db",
       "version": "0.0.1",
@@ -406,6 +418,8 @@
 
     "@reviq/cli": ["@reviq/cli@workspace:apps/cli"],
 
+    "@reviq/common": ["@reviq/common@workspace:packages/common"],
+
     "@reviq/db": ["@reviq/db@workspace:packages/db"],
 
     "@reviq/db-schema": ["@reviq/db-schema@workspace:packages/db-schema"],