spec(port): port specs/port/trios-railway/crates/trios-igla-race/src/invariants.t27 (Closes #9677)

[dmitrii-f-t27]

Summary

Port gHashTag/trios-railway:crates/trios-igla-race/src/invariants.rs (at 8b229e9489ee, 15 lines) as specs/port/trios-railway/crates/trios-igla-race/src/invariants.t27 — Roadmap Stage 6 (goal #4548), target t27c gen-rust. Closes #9677. This is the first spec under specs/port/trios-railway/ — the directory is created by this one file.

The original is the constitutional anchor check: it computes phi as (1 + sqrt(5)) / 2 and verifies phi^2 + 1/phi^2 = 3 within 1e-10. Per the issue's rule ("Port the decision, not the plumbing"), the one listed function is ported under its name as a tested pure decision, and the language's missing sqrt builtin is computed honestly rather than hardcoded:

• sqrt5_newton — Newton's iteration x <- (x + 5/x) / 2, forty rounds from 5.0 (quadratic convergence, far past f64 precision);
• phi_from_sqrt5 — (1 + sqrt(5)) / 2 (original line 2);
• anchor_of_phi — phi^2 + 1/phi^2 (original line 3);
• within_anchor_tolerance — the (anchor - 3).abs() < 1e-10 bound, carried as its decimal form 0.0000000001 (the parser's literal set has no scientific notation) (original line 4);
• check_phi_anchor — the composed check (original lines 1-5), asserted true like the original's own test.

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: 5/5 tested (100%) — no transports in this port.
• t27c test-report: 5 tests / 5 pass / 0 FAIL / 0 BLOCKED, 0 vacuous passes — including the sqrt convergence window (2.2360679774 < s < 2.2360679775), the golden-ratio window, the tolerance bounds on both sides of 3, and the anchor identity at the golden ratio.
• t27c gen | grep -c 'not yet implemented': 0; gen | wc -l: 69 (> 12).
• grep -cE '^\s*(pub )?fn (check_phi_anchor)\(': 1. grep -cE '^\s*test\s+(["|[A-Za-z_])': 5 (≥ 1).
• Boundary: git status --short — exactly this one file. The repo's lefthook pre-commit passed.
• dupe_scan: all 5 names unique across 2040 specs; the bare body scan adds no duplicate group (752 bodies / 221 groups on base, identical with this spec present).

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 the merge itself needs your action.

What this is: the #9677 port — crates/trios-igla-race/src/invariants.rs (gHashTag/trios-railway, at 8b229e9489ee, 15 lines) re-authored as specs/port/trios-railway/crates/trios-igla-race/src/invariants.t27. One file (the first under specs/port/trios-railway/), head 17f13be53, Closes #9677.

What is verified:

• t27c parse OK, spec-status IMPLEMENTED, typecheck 0 errors / 0 warnings, coverage 5/5 (100%) — no transports, t27c test-report 5 tests / 5 pass / 0 FAIL / 0 BLOCKED, 0 vacuous.
• The missing sqrt builtin is computed honestly: Newton's iteration x <- (x + 5/x)/2 (forty rounds, far past f64 precision), asserted into its convergence window; phi, the anchor phi^2 + 1/phi^2 and the 1e-10 tolerance bound are each ported and tested; the composed check_phi_anchor passes like the original's own test.
• gen → 69 lines, 0 not yet implemented; fn (check_phi_anchor)( count 1; 5 test blocks; boundary exactly the one file.
• dupe_scan: all 5 names unique across 2040 specs; bare body scan adds no duplicate group (752/221 unchanged).
• The t27b-native-run artifact of this head (commit 17f13be, run 38994045686) — рow: reference pass, t27b pass, tests 5, invariants 0, asserts 13, blockers [], detail empty, reference_disagree: [].

CI (head 17f13be): required trio green — validate, check-linked-issue, parse-ratchet; 26 checks pass overall, incl. emit-bitexact, t27b-native-linux, t27b-native-macos.

The 3 reds are the base-red trio, not this change: cli-tri (the #3324 include_str!), duplicate-bodies (only the known base names), t27b-native-ratchet (the same verdict red the Queen's port PRs carry; this spec's row is reference pass + t27b pass — the registration debt is the UNLISTED class).

After the merge I will: verify the spec file live on the merge SHA, confirm #9677 auto-closed, and file the 14-step report.

Dmitrii Fedorov (@dmitrii-f-t27)

[dmitrii-f-t27]

Correction to my merge request above: the t27b-native-run artifact run id is 38992184549 (the ratchet job of this head), not the number I typed there. The artifact facts stand as verified from the downloaded run.json of that run: commit 17f13be53, invariants.t27 row — reference pass, t27b pass, tests 5, invariants 0, asserts 13, blockers [], detail empty, reference_disagree: [].

Dmitrii Fedorov (@dmitrii-f-t27)