feat: better errors for Node.JS bindings

[barjin]

Closes #397.

[Copilot]

Pull request overview

This PR improves error reporting across the Node.js bindings by propagating more specific native error categories (notably proxy CONNECT failures) and rethrowing them as typed JS error classes, aligning with issue #397’s request for actionable connection-phase failures.

Changes:

• Added new Rust error variants for proxy CONNECT tunnel failures and proxy auth requirements, and attempted to detect these from underlying hyper_util tunnel errors.
• Updated Node.js bindings to emit a stable error code prefix and rethrow native errors as specific JS Error subclasses.
• Pinned tower-http and patched hyper-util to specific git revisions (and updated the lockfile accordingly).

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
impit/src/errors.rs	Adds ProxyTunnelError / ProxyAuthRequired and maps TunnelError into these variants.
impit-python/src/errors.rs	Handles the new Rust variants in Python error conversion (currently mapped to ProxyError).
impit-node/src/lib.rs	Encodes ImpitError variants into string error codes for JS rethrowing.
impit-node/index.wrapper.js	Uses rethrowNativeError on failures and exports the new JS error classes.
impit-node/index.js	Updates native binding version checks to 0.10.1.
impit-node/errors.js	Introduces JS error class hierarchy + rethrowNativeError mapping logic.
Cargo.toml	Pins tower-http and adds a git patch for hyper-util.
Cargo.lock	Reflects the patched/pinned dependency sources.

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[barjin]

cc @Pijukatel the review request is just for learning purposes, as discussed in the meeting yesterday (but ofc feel free to chip in with tips, I don't really like the implementation 😄 )

[barjin]

cc @bliuchak & @daniil-poletaev, please feel free to check if the changes match your expectations

[daniil-poletaev]

Nice, thank you for taking care of this ❤️

Tested it and it works as expected and returns status code

[bliuchak]

Thanks!