test: pin the diffs that still screen (unselectable, skill template + bun.lock)

Two assertions in test/ship-queue-train-logic.test.ts: a diff the paid
selector cannot select recommends --screen with the full gate selection,
and a diff that mixes a skill template with bun.lock recommends --screen.
GSTA-165 1a, from /ship Steps 7-8.

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

test/ship-queue-train-logic.test.ts

@@ -204,9 +204,22 @@ describe('screen recommendation', () => {
     const shared = await gstackPaidSelection(ROOT, 'HEAD', ['bun.lock'], has);
     expect(shared.recommend).toBe('screen');
     expect(shared.lines[2]).toMatch(/^SCREEN: selector mode full-fallback \(.*bun\.lock.*\) → recommend --screen$/);
+    expect((await gstackPaidSelection(ROOT, 'HEAD', ['review/SKILL.md.tmpl', 'bun.lock'], has)).recommend).toBe('screen');
     const docs = await gstackPaidSelection(ROOT, 'HEAD', ['docs/ship-policy.md'], has);
     expect(docs.recommend).toBe('no-screen');
   }, 60_000);
+
+  // Generated by /ship Step 7 coverage audit (GSTA-165 1a).
+  // Value: protects=a diff the paid selector cannot select (needs full validation) recommends --screen with the full gate selection;
+  //   fails_when=the selector-error branch stops forcing everyCase, so an unselectable diff rides the train unscreened;
+  //   why_new=the existing selector test covers pr, dependents and full-fallback modes only, never the throw;
+  //   seam=none; no_claim=dispatch of the screen itself (pure selection on gstack's own tree; no eval-bg run)
+  test("gstack's selector on gstack's own tree: a diff it cannot select recommends --screen with the full gate selection", async () => {
+    const r = await gstackPaidSelection(ROOT, 'HEAD', ['unregistered/nested/SKILL.md'], () => false);
+    expect(r.recommend).toBe('screen');
+    expect(r.lines[0]).toMatch(/^SCREEN: selection \d+ e2e case\(s\) \+ \d+ judge\(s\) \(the PR profile needs full validation \(.*requires full validation.*\): the screen is the full gate selection\)$/);
+    expect(r.lines[2]).toBe('SCREEN: the selector could not select → recommend --screen');
+  }, 60_000);
 });
 
 describe('the train policy block', () => {