Add organized userscript collection

[jeeftor]

Summary

• preserve the existing Free Press audio downloader at the root update URL path
• add organized userscript directories for Abook NZB Helpers, NZBKing Named Downloader, and ttyd OSC52 Clipboard
• add README docs, Makefile targets, and Node-based userscript metadata checks

Verification

• npm test
• node --check thefp.js
• node --check scripts/abook-nzb-helpers/abook-nzb-helpers.user.js
• node --check scripts/nzbking-named-downloader/nzbking-named-downloader.user.js
• node --check scripts/ttyd-osc52-clipboard/ttyd-osc52-clipboard.user.js
• make list