spec(port): port specs/port/trios-railway/crates/trios-igla-race/src/bin/smoke_agent.t27 (Closes #9714)

[dmitrii-f-t27]

Summary

Port gHashTag/trios-railway:crates/trios-igla-race/src/bin/smoke_agent.rs (at 46ea51e585ee, 86 lines) as specs/port/trios-railway/crates/trios-igla-race/src/bin/smoke_agent.t27 — Roadmap Stage 6 (goal #4548), target t27c gen-rust. Closes #9714.

The original is ADR-002's synthetic smoke agent: it runs a 1-step experiment to prove the pipeline is alive, with a feature gate, CLI defaults and a pass rule.

Per the issue's rule ("Port the decision, not the plumbing"), the one listed function is ported under its name as a pure function (no transports — the tracing subscriber, the run_local call and the prints are the callers' plumbing) with 5 tests (19 runtime asserts, 0 vacuous, 100% function coverage):

• the CLI defaults (original lines 27-31): --steps 1, --seed 42 — what a bare invocation runs with;
• the pass rule (lines 66-76): the smoke run passes when it produced at least one jsonl line per requested step — jsonl_lines >= steps; fewer lines than steps fails;
• the fail_on_error exit (lines 71-73): a failing run exits 1 only when --fail-on-error was asked for; without the flag the run still ends Ok (exit 0);
• main's smoke-feature gate (lines 81-84): without the 'smoke' feature the agent bails with exit 1 before any run; the bail text is carried as a const.

Verification (all run live from the worktree root, zig 0.16.0)

• t27c parse: OK. t27c spec-status: IMPLEMENTED. t27c typecheck: 0 errors, 0 warnings.
• t27c coverage: 3/3 tested (100%) — no transports in this port.
• t27c test-report: 5 tests / 5 pass / 0 FAIL / 0 BLOCKED, 0 vacuous passes — the defaults, the pass rule at/below/beyond the step count, the feature gate with and without the feature, and the fail_on_error exit both ways.
• t27c gen | grep -c 'not yet implemented': 0; gen | wc -l: 69 (> 12).
• grep -cE '^\s*(pub )?fn (main)\(': 1. grep -cE '^[[:space:]]*test[[:space:]]+("|[A-Za-z_])': 5 (≥ 1).
• Boundary: git status --short — exactly this one file. The repo's lefthook pre-commit passed.
• dupe_scan: both helper names unique across 2059 specs (checked before the commit); the bare body scan adds no duplicate group and none of the known groups grew.

Dmitrii Fedorov (@dmitrii-f-t27)

[dmitrii-f-t27]

@gHashTag Please merge this PR into master via the golden chain — rights on gHashTag/t27 are read-only for me (403), so only you can merge it.

Note: the first CI round had duplicate-bodies red — that was the put_lit/put_range twin pair against the then-base, fixed upstream by a19701a (ci(dupe): bless the two deliberate put copies in the NMSE run harness); I merged the fresh master into this branch (merge commit d9df482, carrying the Closes reference) and every check is green again except the known base-red pair.

Verification of this head (d9df482):

• Required CI trio green: validate, check-linked-issue, parse-ratchet; also Check L1 TRACEABILITY, Corpus ratchet and duplicate-bodies green.
• The t27b-native-run artifact of this head (commit d9df482, run 39052792819) row for specs/port/trios-railway/crates/trios-igla-race/src/bin/smoke_agent.t27: reference pass, t27b pass, tests 5, invariants 0, asserts 18, blockers [], detail empty, reference_disagree: [].
• The only red checks are the known base-red pair (cli-tri ci: repair the two workflows whose failure was in the workflow #3324 include_str!, t27b-native-ratchet registration debt) — both red on master without this PR; no other check is red.

After the merge I will: verify the spec file live on the merge SHA, confirm #9714 auto-closed, and file the 14-step report.

Dmitrii Fedorov (@dmitrii-f-t27)