feat(#25): scope gsd-verifier Step 7b to enumerate-or-single-test; forbid full-suite re-runs (#753)

* feat(#25): scope gsd-verifier Step 7b to enumerate-or-single-test; forbid full-suite re-runs

Step 7b's lone test example (`npm test -- --grep "$PHASE_TEST_PATTERN"`) is
mocha/vitest/jest-specific, where `--grep` filters which tests *execute*. Models
generalized it to `cargo test --workspace 2>&1 | grep X` (runs the whole suite,
filters only *output*) and repeated it once per must-have, adding minutes per
verification with no new evidence after the first run.

Replace the example with language-agnostic guidance: prove a test EXISTS via
enumeration (`cargo test -- --list` / `pytest --collect-only` / `npx vitest
list` / `go test -list`), and prove it PASSES via a single named test
(`cargo test <name> -- --exact` / `pytest -k` / `npx vitest run -t`). Add a
Spot-check constraint forbidding more than one full-suite run per verification
or piping a full run through grep per must-have, while still permitting one
saved run + grep when a full run is genuinely required. docs/AGENTS.md gains a
one-line Key-behaviors note, and a new test asserts the Step 7b content.

Scoped per the maintainer decision on the issue: folded into Step 7b (no new
top-level Step 7a) with no VERIFICATION.md label changes.

Closes #25

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* chore(#25): add Changed changeset fragment for PR #753

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

docs/AGENTS.md

@@ -292,6 +292,7 @@ GSD uses a multi-agent architecture where thin orchestrators (workflow files) sp
 - Logs issues for `/gsd-verify-work` to address
 - Milestone scope filtering: gaps addressed in later phases are marked as "deferred", not reported as failures (v1.32)
 - **Test quality audit** (v1.32): verifies that tests prove what they claim by checking for disabled/skipped tests on requirements, circular test patterns (system generating its own expected values), assertion strength (existence vs. value vs. behavioral), and expected value provenance. Blockers from test quality audit override an otherwise passing verification
+- Runs the full workspace test suite at most once per verification — proves a test *exists* by enumeration and that it *passes* via a single named test, never re-running the whole suite per must-have.
 
 ---