feat: Replace axios with native fetch API

[TNAJanssen]

Summary

This PR migrates the codebase from axios to the native fetch API, removing the external dependency while maintaining all existing functionality.

Changes Made

🔧 Core Migration

• Removed axios dependency from package.json
• Created fetch wrapper (src/fetchUtils.js) with:
  • Custom error handling with FetchError class
  • isAbortError() helper for cancellation detection
  • Response interceptor pattern for retry logic
  • Automatic content-type handling

🔄 Request Cancellation

• Replaced axios.CancelToken with native AbortController
• Updated all React hooks to use AbortController for cleanup
• Maintains proper request cancellation on component unmount

🔁 Retry Logic

• Preserved automatic retry behavior for Dymo service discovery
• Continues scanning ports 41951-41953 on both 127.0.0.1 and localhost
• Maintains localStorage caching of successful connection parameters
• Skips retry on HTTP 500 errors and aborted requests (same as before)

📝 Additional Fixes

• Fixed missing moment.js import in storage.js by removing unused expiration logic (separate commit)

Testing

• ✅ Build passes without errors
• ✅ ESLint passes without warnings
• ✅ All existing APIs maintain the same interface
• ⚠️ Manual testing with Dymo hardware recommended

Breaking Changes

None - the API remains identical for consumers of this library.

Browser Compatibility

The fetch API and AbortController are well-supported in modern browsers. For older browser support, polyfills may be needed.

[apenab]

Hi @TNAJanssen , thx for the contribution, I'll try to review the PR ASAP.