Add send-to-kindle extension

[lemikeone]

Description

This PR introduces the Send to Kindle Raycast extension.

It allows sending the current web article to Kindle with a clean reading format.

What this extension does

• Extracts readable article content from the active tab
• Converts content into EPUB for Kindle
• Supports two sending methods:
  • Email delivery (SMTP)
  • Open with the Send to Kindle desktop app
• Provides both:
  • Direct send command
  • Preview + edit before send command

Main features

• Readability-based extraction (@mozilla/readability)
• Per-domain cleanup rules ("Skills") with CSS selectors
• Optional cover image selection via Cover CSS
• Optional removal of all links before sending
• Skill management (add/edit/delete + JSON export)
• Sending method setup and validation flow

Included commands

• Send to Kindle
• Preview and Send to Kindle
• Set / Change Sending Method
• Add a Skill
• My Skills

Notes

• Platform: macOS (needs to be tester on Windows)
• Category: Productivity
• License: MIT

Screencast

Screencast : https://share.cleanshot.com/X4zBr9jh3w9mnWNn7Dp6

Checklist

• I read the extension guidelines
• I read the documentation about publishing
• I ran npm run build and tested this distribution build in Raycast
• I checked that files in the assets folder are used by the extension itself
• I checked that assets used by the README are placed outside of the metadata folder