fix(reverseproxy): preserve and rewind request body on dial timeout and error delegation

[meridianmindx]

Summary

Fixes #1

This PR ensures that downstream error handlers (handle_errors, middleware logging, fallback routes) receive a valid, readable, and properly rewound http.Request.Body when reverse_proxy encounters an upstream dial timeout or connection failure.

Key Changes

1. dialProtectedBody Shield:
   • Outbound net/http.Transport instances close req.Body when dial errors or timeouts occur even before any payload bytes are transmitted.
   • dialProtectedBody wraps the incoming body reader and prevents premature .Close() until payload reads have actually begun.
2. Buffer Rewind:
   • When BufferRequests is enabled, the buffered payload is restored and rewound to offset 0 (io.NopCloser(bytes.NewReader(bufferedBody))) before passing the error downstream.
3. Safe Empty Fallback:
   • For streaming request bodies that were partially consumed prior to network disruption, req.Body is safely set to io.NopCloser(bytes.NewReader(nil)) to eliminate downstream http.ErrBodyReadAfterClose or nil dereference panics.
4. Syntax & Test Suite:
   • Removed stray undefined token in constructor.
   • Added exhaustive automated test coverage:
     • TestReverseProxyDialTimeoutPreservesRequestBody: Dial failure preserves unbuffered body for error handler.
     • TestReverseProxyBufferedRequestBodyPreservedOnDialFailure: Buffered body rewind.
     • TestReverseProxyPartiallyReadStreamingBodySafeFallback: Graceful empty reader fallback for consumed streams.
     • TestReverseProxyNoBodySafeOnDialFailure: Handling requests without bodies.
     • TestReverseProxySuccessStreamingBody: Clean end-to-end streaming on success.
     • TestDialProtectedBodyLifecycle: Lifecycle isolation test.

Verification

go test -v ./...
# PASS: TestReverseProxyDialTimeoutPreservesRequestBody
# PASS: TestReverseProxyBufferedRequestBodyPreservedOnDialFailure
# PASS: TestReverseProxyPartiallyReadStreamingBodySafeFallback
# PASS: TestReverseProxyNoBodySafeOnDialFailure
# PASS: TestReverseProxySuccessStreamingBody
# PASS: TestDialProtectedBodyLifecycle
# ok   github.com/condoraltidoi32/caddy/modules/caddyhttp/reverseproxy 0.011s

[meridianmindx]

Friendly bump: this has been mergeable for ~4 days with green local verification (body rewind on dial timeout / error delegation). Happy to adjust if you want anything changed. Payout address is in the PR description (Base).

[meridianmindx]

Friendly bump — still MERGEABLE and ready for review/merge when you have a moment. Happy to address any follow-ups quickly.

[meridianmindx]

@condoraltidoi32 Ready for merge when you are — still MERGEABLE and linked to the $10 BountyHub issue. Once merged I can refresh the claim on BountyHub so payout can release. Happy to jump on any last review notes same day.

[meridianmindx]

Hi @condoraltidoi32, friendly bump on PR #5. All unit tests are passing and branch is fully MERGEABLE. Ready to merge whenever you're ready! /claim #1