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/frontend-utils/README.md

@@ -0,0 +1,15 @@
+# @reviq/frontend-utils
+
+Frontend-specific utilities for the RevIQ publisher dashboard.
+
+## Usage
+
+```typescript
+import { getOrgColor, getOrgInitials } from "@reviq/frontend-utils";
+```
+
+## Exports
+
+- `getOrgInitials(org)` - Get display initials from an organization's slug or display name
+- `getOrgColor(org)` - Get a consistent HSL color based on the organization slug
+- `OrgLike` - Type interface for organization objects