Update rss recipe

[jsantell]

Summary by cubic

Updated the RSS importer to use a lightweight, built-in DOM parser and a reactive fetch/parse pipeline, reducing dependencies and preventing duplicates. The UI was simplified and sensible defaults were added for easier setup.

• New Features

  • Added a minimal DOMParser for XML/HTML with basic selectors.
  • Included a test validating XML parsing against an Atom sample.

• Refactors

  • Reworked rss.tsx to use fetchData + derive + lift and split parsing into parseRSSFeed.
  • Switched to ct-input and inline style objects; removed the “Import Limit” input.
  • Improved Atom detection and item de-duplication using a Set of IDs.
  • Set default settings in the recipe (feedUrl "", limit 100).