🧪 Improve test coverage to 99%

Add comprehensive tests for:
- viewport utilities (parseViewport, formatViewport, setViewport, getCommonViewports)
- pattern matching (matchPattern, filterByPattern, findMatchingHook edge cases)
- screenshot functions (captureScreenshot, captureAndSendScreenshot)
- crawler functions (readIndexJson, discoverStories, generateStoryUrl validation)

Coverage: 99.33% lines, 92.86% branches, 97.06% functions

Author: Robdel12