fix(lsp): address reviewer blockers — remove duplicate step, move LspError import, fix metadata

- Remove duplicate @then("ltcov the transport should be alive") in
  features/steps/lsp_transport_coverage_steps.py; the same step is
  already defined at features/steps/lsp_transport_post_spawn_cleanup_steps.py:92
  for issue #7044. The duplicate caused AmbiguousStep at behave load
  time, erroring every BDD feature in the suite (root cause of the
  CI unit_tests + coverage gate failures).
- Remove redundant inline `from cleveragents.lsp.errors import LspError`
  inside StdioTransport.start(); the module-level import at line 30
  is sufficient and inline imports violate the project import rule.
- Update CONTRIBUTORS.md: correct the PR number from #11160 (the
  linked issue) to #11185 (this PR).
- features/lsp_transport_subprocess_cleanup.feature: add the required
  `@tdd_issue @tdd_issue_11160` tags per the TDD bug-fix workflow,
  fix the `returnscode` typo in a scenario name, and rename the
  `dye_on_start` command label to `die_on_start`.

ISSUES CLOSED: #11160

CONTRIBUTORS.md

@@ -120,4 +120,4 @@ Below are some specific details of individual PR contributions.
 * Jeffrey Phillips Freeman has contributed the `--format`/`-f` flag to `agents session tell` (issue #10466): adds JSON envelope output for machine-readable workflows alongside existing Rich console output, with Behave BDD test coverage verifying all four non-rich format paths (JSON, YAML, plain, table) and the short `-f` flag alias.
 * HAL 9000 has contributed the Semgrep guard for broad exception suppression (PR #9185 / issue #9103): added two new Semgrep rules (`python-no-suppressed-exception` and `python-no-suppress-exception`) to automate enforcement of error propagation guidelines, integrated Semgrep into `nox -s lint` in audit mode with migration plan for ~337 existing violations, and comprehensive BDD test coverage across all rule patterns and escape hatch scenarios.
 * HAL 9000 has contributed the `ProviderRegistry.FALLBACK_ORDER` fix (#10906): added the missing `ProviderType.GEMINI` to the fallback provider order list so that when only a Gemini API key is configured, the registry correctly selects it as the default provider. Includes BDD regression scenarios in `features/fallback_gemini_provider.feature`.
-* HAL 9000 has contributed the StdioTransport subprocess cleanup on failed initialization fix (PR #11160 / issue #11160): after ``start()`` spawns a process with ``subprocess.Popen()``, the method now verifies the process is still alive via ``poll()``. If it died immediately during initialization, ``stop()`` is called to release the handle and an ``LspError`` with exit code is raised, preventing zombie processes and resource leaks. Includes BDD test coverage in ``features/lsp_transport_subprocess_cleanup.feature``.
+* HAL 9000 has contributed the StdioTransport subprocess cleanup on failed initialization fix (PR #11185 / issue #11160): after ``start()`` spawns a process with ``subprocess.Popen()``, the method now verifies the process is still alive via ``poll()``. If it died immediately during initialization, ``stop()`` is called to release the handle and an ``LspError`` with exit code is raised, preventing zombie processes and resource leaks. Includes BDD test coverage in ``features/lsp_transport_subprocess_cleanup.feature``.

features/lsp_transport_subprocess_cleanup.feature

@@ -1,3 +1,4 @@
+@tdd_issue @tdd_issue_11160
 Feature: StdioTransport subprocess cleanup on failed initialization
   As a developer maintaining the LSP transport layer
   I need proper cleanup of subprocess handles when the process dies during start()
@@ -27,14 +28,14 @@ Feature: StdioTransport subprocess cleanup on failed initialization
     When ltcov I try to start the transport
     Then ltcov the error should be an LspError with message "died on spawn"
 
-  Scenario: start raises LspError when process returnscode is zero (clean exit)
+  Scenario: start raises LspError when process returncode is zero (clean exit)
     Given ltcov I create a StdioTransport for command "quick_exit"
     And ltcov Popen is mocked to return a process that exited with code 0
     When ltcov I try to start the transport
     Then ltcov the error should be an LspError with message "died on spawn"
 
   Scenario: stop() handles already-exited process and cleans up _process
-    Given ltcov I create a StdioTransport for command "dye_on_start"
+    Given ltcov I create a StdioTransport for command "die_on_start"
     And ltcov Popen is mocked to return a process that exited with code 42
     When ltcov I try to start the transport
     Then ltcov the stop handles already-exited processes correctly

features/steps/lsp_transport_coverage_steps.py

@@ -543,11 +543,6 @@ def step_ltcov_process_none_after_failed_start(context: Context) -> None:
 # ---------------------------------------------------------------------------
 
 
-@then("ltcov the transport should be alive")
-def step_ltcov_alive(context: Context) -> None:
-    assert context.ltcov_transport.is_alive, "Expected transport to be alive"
-
-
 @then("ltcov no error should have been raised")
 def step_ltcov_no_error(context: Context) -> None:
     assert context.ltcov_error is None, (

src/cleveragents/lsp/transport.py

@@ -107,8 +107,6 @@ class StdioTransport:
         if self._process is not None and self.is_alive:
             raise RuntimeError("Transport already started")
 
-        from cleveragents.lsp.errors import LspError
-
         merged_env = {**os.environ, **self._env}
         cmd = [self._command, *self._args]