fix(cli): handle whitespace-only Redis_URL properly

[vchomakov]

Summary

Fixes validation of Redis URL parameter to properly handle whitespace-only values. Previously, URLs containing only whitespace characters would pass validation but cause parsing errors.

Changes

• Added url.strip() check in CLI URL validation
• Prevents processing of empty or whitespace-only URLs
• Maintains existing behavior for valid URLs

Testing

• Tested with empty string URL
• Tested with whitespace-only URL (" ", "\n\t")
• Tested with valid URLs (no regression)
• Existing tests pass

Example

# Before: Would cause parsing error
redis-mcp-server --url "   "

# After: Gracefully skips invalid URL and uses defaults
redis-mcp-server --url "   "

[tishun]

LGTM