ci(mutants): an unmatched --test-name-pattern is setup-failure, not survived (#650)

A name-filtered `node --test` that matches no test exits 0 and TAP reports
only the file itself. The clean run took that for a healthy witness and the
mutant run for `survived`, although no assertion ran either time — as in
Validate 36151140394 on #649, where a renamed test left a guard pattern empty.

- mutation-guard-outcome: nodeTestSelection/executedTestNames/
  emptyTestSelection; a green oracle with a name filter and zero executed
  named tests is `setup-failure` (clean run: «FAIL чистая подготовка»,
  diff mode: attributed like any setup failure, #568).
- mutation-gate --check: staticTestSelectionProblems — every pattern must
  match a literal test(/it(/describe( name in the guard's files; files with
  ${…} names only warn. POSIX quoting keeps \( inside "…".
- Registry today: 349 unique name-filtered commands run on dev, all execute
  ≥ 1 test; --check: 0 errors, 3 warnings (dynamic names).
- Tests: 6 new in test/mutation-guard-outcome.test.mjs (incl. the installed
  node's real TAP and a registry-wide static check); 3 mutants.
- Docs: TESTING.md pointer, testing-notes/infrastructure.md section.

Issue: #650
User-Visible: no

docs/testing-notes/README.md

@@ -105,6 +105,7 @@
 - [Lazy editor runtime and frontend asset tree (#337)](infrastructure.md#lazy-editor-runtime-and-frontend-asset-tree-337)
 - [Съёмка документации запускается с флагами детерминизма (#424)](infrastructure.md#съёмка-документации-запускается-с-флагами-детерминизма-424)
 - [Воспроизводимость съёмки документации (#410, #422)](infrastructure.md#воспроизводимость-съёмки-документации-410-422)
+- [Пустое совпадение `--test-name-pattern` (#650)](infrastructure.md#пустое-совпадение---test-name-pattern-650)
 
 ## [История прогонов и партий](history.md)