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

scripts/mutation-gate.mjs

@@ -24,7 +24,9 @@ import {
 } from './mutation-evidence.mjs';
 import { attributeSetupFailure } from './mutation-attribution.mjs';
 import { guardEnvironment, planEnvironment, planEnvironmentLines } from './mutation-environment.mjs';
-import { MUTATION_OUTCOME, isProofOutcome } from './mutation-guard-outcome.mjs';
+import {
+  MUTATION_OUTCOME, isProofOutcome, staticTestSelectionProblems,
+} from './mutation-guard-outcome.mjs';
 
 const repoRoot = fileURLToPath(new URL('..', import.meta.url));
 
@@ -151,6 +153,11 @@ export async function main(argv) {
 
   if (argv.includes('--check')) {
     let stale = 0;
+    let warned = 0;
+    const readTest = (file) => {
+      const path = join(repoRoot, file);
+      return existsSync(path) ? readFileSync(path, 'utf8') : null;
+    };
     for (const m of selected) {
       try {
         // #499: бандл мутанта собирает раннер (`buildBundle`, только rollup +
@@ -165,12 +172,21 @@ export async function main(argv) {
           const hits = source.split(patch.find).length - 1;
           if (hits !== 1) throw new Error(`якорь найден ${hits} раз(а)`);
         }
+        // #650: a name filter that matches nothing makes the witness vacuous.
+        const selection = staticTestSelectionProblems(m.guard, readTest);
+        const error = selection.find((problem) => problem.level === 'error');
+        if (error) throw new Error(error.text);
+        for (const problem of selection) {
+          console.log(`WARN ${m.id}: ${problem.text}`);
+          warned++;
+        }
         console.log(`ok   ${m.id}`);
       } catch (error) {
         console.log(`FAIL ${m.id}: ${error.message}`);
         stale++;
       }
     }
+    if (warned) console.log(`предупреждений о шаблонах имён: ${warned}`);
     reportPlanMetrics();
     return stale ? 2 : 0;
   }