refactor!: overhaul internal impl

[pi0]

This PR refactors crossws internal implementation to be more future-ready and web-compatible.

Changes (WIP):

• Core crossws is rewritten as a (much faster) class
• upgrade hook is first called on global and then resolved hook
• The upgrade hook can return a standard web Response to abort (Allow upgrade hook to return custom response #16)
• Added proxy stubs for Node (and UWS.js) for partial (web standard) request/response support
• Bun integration needs an explicit upgrade header check to allow response abortions
• Added additional tests for headers (incoming and response)
• Support closeAll for Node.js adapter (subject to change before release mainly for tests)
• Peers have standard, tested and consistent peer.headers and peer.url props.

[cloudflare-workers-and-pages]

Deploying crossws with    Cloudflare Pages

Latest commit:	d57cf40
Status:	✅  Deploy successful!
Preview URL:	https://4d9a8008.crossws.pages.dev
Branch Preview URL:	https://refactor-internal-overhaul.crossws.pages.dev

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