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/README.md

@@ -0,0 +1,24 @@
+# @reviq/server-utils
+
+Server and CLI utilities for the RevIQ platform. These utilities use crypto APIs and are designed for Cloudflare Workers compatibility.
+
+## Usage
+
+```typescript
+import {
+  generateSecureBase58Token,
+  hashPassword,
+  verifyPassword,
+} from "@reviq/server-utils";
+```
+
+## Exports
+
+### Token Generation
+- `generateSecureBase58Token(prefix)` - Generate a secure random token with a prefix (e.g., `reviq_`)
+- `parseBase58Token(token)` - Parse and validate a base58-encoded token
+- `isBase58(str)` - Check if a string is valid base58
+
+### Password Hashing
+- `hashPassword(password)` - Hash a password using PBKDF2-SHA256
+- `verifyPassword(password, hash)` - Verify a password against a stored hash