Nothing checks whether a seal gen_hash still matches what the compiler emits; 116 were stale

[gHashTag]

A seal records four gen_hash_* fields — the hashes of what each backend emitted. Those are the fields that make it a claim about generated code rather than about a file listing.

Nothing checks them.

Measured on master, before this

gen_hash_rust stale	109
gen_hash_zig stale	7
gen_hash_c stale	0
gen_hash_verilog stale	0
spec_hash stale	0

The 116 were left by five merged backend repairs — #3401, #3403, #3405, #3407, #3411 — which are mine. Every one of them changed emitted Rust, and none of them touched a spec, so spec_hash stayed correct and every coverage and staleness check in the repository stayed green while a sixth of the Rust seals described output the compiler no longer produces.

What the existing checks actually cover

• check_seal_coverage.py — does a seal describe a spec that exists, unchanged at source. It is about spec_path and spec_hash.
• Seal Staleness Warning — the NMSE manifest seal, sha256(bootstrap/src/compiler.rs) against FROZEN_HASH. Unrelated to .trinity/seals, and it always exits 0 by design.
• t27c seal --verify <spec> — answers exactly this question, per spec, with a precise MISMATCH line. Nothing called it across the corpus.

Controls, so this is a finding and not a broken probe: --verify exits 1 on specs/ar/restraint.t27 with gen_hash_rust: MISMATCH (saved=7d50c681…, current=e60d0df7…) and the other three MATCH; it exits 0 on specs/fpga/testbench/apb_bridge_tb.t27.

Two things found while repairing it

1. The seal set is duplicated. 1313 seals for 728 distinct specs; 547 specs carry more than one seal file. t27c seal --save writes to .trinity/seals/<module>.json — one name — so refreshing through the tool fixed 116 → 58 and left every duplicate stale. Some of the duplicate names are not module names at all:

specs/tri/utils/logger.t27 -> [[]const u8.json, utils_[]const u8.json, utils_TriLogger.json]

A seal named after a type string. Which name is canonical is a decision, and the cleanup is filed rather than done here.

2. gen_hash=none is a separate debt and is counted apart. 169 seals record none for at least one backend — the backend rejected the spec when it was sealed. --save refuses to overwrite those ("4 of 4 backends rejected it"), so they need a different repair and would otherwise inflate the headline. That 169 independently reproduces the figure an earlier audit reported for none == none seals.