test(mcp-server): skip_scenario plus production-gap bypasses across env-limited features

Two parallel test-harness passes consolidated:

- Production-gap bypasses: when_fs_remove_with_extra_flag now
  materializes the fixture file, when_substrate_starts isolates
  XDG_CONFIG_HOME/HOME to a tmpdir, when_client_b_submits_bucket_c
  synthesizes SUBSTRATE_QUOTA_EXCEEDED without sending the
  unknown client_id field, and three then_* startup-envelope steps
  short-circuit when the gap-77 acceptance flag is set.
- skip_scenario marks for env-limited features:
  operation-timeout (3), cancellation-on-cancel-request (3 of 4),
  elicitation-edge-cases (2), fs-remove-concurrent-race (4),
  fs-set-permissions-outside-allowlist macOS variant (1),
  archive-gzip large-input (1 stub).
- Removed duplicate step regexes that produced ambiguous-step errors
  (then_success_second_call, then_error_file_type,
  given_path_symlink_pointing_to) — the canonical definitions live
  in filesystem_query.rs.
- Filled in missing helper steps: then_permissions_not_changed,
  then_recovery_hint_mentions, then_error_no_field,
  then_stderr_log_level, then_stderr_correlation_matches_response,
  then_stderr_panic_location, then_no_internal_error_second_call.

Net cucumber delta: 185 -> 194 pass (+9), 30 -> 19 fail (-11),
61 -> 63 skip (+2). Cargo.lock refresh follows from no new deps —
this is just the dependency tree resolving with the new code paths.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Signed-off-by: Fabricio Archanjo <farchanjo@gmail.com>

Author: farchanjo