Failing vMCP k8s e2e test

[dmjb]

Bug description

During the period of broken builds around 4th-5th Dec, a vMCP change was merged which either introduced a broken test, or caused a test to fail. This test has been commented out for now.

The test is "Inline Auth with Anonymous Incoming when using anonymous incoming with inline outgoing auth should proxy tool calls with inline auth configuration" which is run as part of the k8s e2e test suite.

This failure was reproduced in multiple PRs which did

Steps to reproduce

Uncomment out the test and run it.

Expected behaviour

Test passses.

Actual behaviour

------------------------------
VirtualMCPServer Inline Auth with Anonymous Incoming when using anonymous incoming with inline outgoing auth should proxy tool calls with inline auth configuration
/home/runner/work/toolhive/toolhive/test/e2e/thv-operator/virtualmcp/virtualmcp_inline_auth_test.go:124
  STEP: Creating MCP client with anonymous auth @ 12/05/25 12:35:05.745
  STEP: Listing and calling backend tool through inline auth proxy @ 12/05/25 12:35:05.766
  Calling tool 'backend-fetch-inline-anon_fetch' with anonymous incoming and inline outgoing auth
  [FAILED] in [It] - /home/runner/work/toolhive/toolhive/test/e2e/thv-operator/virtualmcp/virtualmcp_inline_auth_test.go:170 @ 12/05/25 12:35:35.828
  STEP: Cleaning up test resources @ 12/05/25 12:35:35.828
• [FAILED] [30.101 seconds]
VirtualMCPServer Inline Auth with Anonymous Incoming when using anonymous incoming with inline outgoing auth [It] should proxy tool calls with inline auth configuration
/home/runner/work/toolhive/toolhive/test/e2e/thv-operator/virtualmcp/virtualmcp_inline_auth_test.go:124

  [FAILED] Tool call should succeed with inline auth
  Unexpected error:
      <*transport.Error | 0xc0006f2790>: 
      transport error: failed to send request: failed to send request: Post "http://localhost:30018/mcp": EOF
      {
          Err: <*fmt.wrapError | 0xc000073e80>{
              msg: "failed to send request: failed to send request: Post \"http://localhost:30018/mcp\": EOF",
              err: <*fmt.wrapError | 0xc000073e40>{
                  msg: "failed to send request: Post \"http://localhost:30018/mcp\": EOF",
                  err: <*url.Error | 0xc00054fd40>{
                      Op: "Post",
                      URL: "http://localhost:30018/mcp",
                      Err: <*errors.errorString | 0x257ecd0>{s: "EOF"},
                  },
              },
          },
      }
  occurred
  In [It] at: /home/runner/work/toolhive/toolhive/test/e2e/thv-operator/virtualmcp/virtualmcp_inline_auth_test.go:170 @ 12/05/25 12:35:35.828
------------------------------

Environment (if relevant)

Github actions.

Additional context

N/A

[yrobla]

@dmjb do you know if that's still happening? Related pr landed #2901