feat(checks): the detector becomes a gate, and our own page had to pass it

[Tradebaas]

What changed and why

Groundwork had 22 gates and not one of them looked at what an interface renders. Ticket 05 of spec
011 wires the design method's deterministic detector into the mechanical floor, in both places the
spec asked for.

The edit hook rides with the payload. checks/design-method.mjs --install no longer passes
--no-hooks, so the install wires the Claude manifest into .claude/settings.local.json (now
ignored by this repo, not only by one machine's global ignore), guarded by upstream so a clone
without the payload is a no-op rather than an error.

The CI half is stack's to wire, beside the ecosystem's typecheck and tests. Section 3 carries
the stage, the runner note (the method's engines.node can sit above the one the rest of CI uses),
the refusal to fall back to green, and what the standards file must say about waivers. This repo's
own workflow gets a design job on Node 22 that scans the published page.

stack-gates grew a second half on the same evidence rule as the first.
.impeccable/config.json is the tracked declaration that this project judges an interface with the
method, because the payload is gitignored and a clone's disk cannot answer that question. While it
is there, a workflow has to actually run the detector; a commented stage fails, exactly like the
commented stack gates next to it.

Then the gate turned on our own landing page, and it had findings. The published CLI is
stricter than the detector bundled with the installed payload: nine findings against none on the
same file, same version. Three were real and are fixed (a tracked-caps pill above the h1, a heading
skipping h2 to h4, 11.5px body text). Four are waived in .impeccable/config.json, each scoped to
that one file with its reason on the entry: three cramped-padding hits proven a false positive
with a five-line fixture, and flat-type-hierarchy on the owner's call with the measurement in the
reason. Two more waivers from the same run predate them, both owner-confirmed: Inter as the body
face, and the tool marquee.

Verified by

• Both directions in real CI, not reasoned about. A gradient headline on index.html turned
  the design job red (run 31212639013, throwaway branch since deleted); the fixed page is green
  (run 31213510003), with gate, drill and trace green beside it.
• The gate watched failing on this repo, not only in fixtures: commenting the detector stage
  out makes node checks/check.mjs report stack-gates, and restoring it clears the run.
• Five new fixtures in checks/check-stack.test.mjs cover the design half in both directions,
  including the commented-stage case and a copy with no design method at all. Suites: 187 across
  the five gate suites (10 stack), and the five node:test suites exit 0.
• The edit hook was exercised on a real payload and reported both tells in a probe file; it
  also fired on the live edits in this session.
• The page was rendered and looked at after the eyebrow change, with animations settled, not
  only re-scanned.
• Measured, not assumed: both detector engines were called directly on the same file with and
  without project config, to rule out config and design-system context as the cause of the gap.
• Not verified here: whether upstream intends the two engines to differ. Our side reads the
  stricter one in CI and says so in stack, so the hook's silence is never taken for the gate's
  verdict.

🤖 Generated with Claude Code