Add JSR Package Support for Spry CLI

[sijucj]

Spry currently does not provide an official distribution via JSR (jsr.io). Adding JSR package support will allow Spry to be consumed seamlessly across Deno, Node.js, and Bun, improving developer adoption and interoperability.

• Spry is published and visible on jsr.io
• Users can install Spry using: deno add jsr:@programmablemd/spry
• Users can install Spry using: npm install jsr:@programmablemd/spry
• Documentation is updated with JSR usage instructions