fix(signals): match hyphenated test-only no-issue rationale

src/signals/engine.ts

@@ -4958,7 +4958,9 @@ export function hasClearNoIssueRationale(pr: Pick<PullRequestRecord, "title" | "
   // spelling this function's own docstring uses — the dominant GitHub/Conventional-Commits form. A bare
   // `docs? only` missed the hyphen, so a docs-only PR with no linked issue was wrongly denied a clear
   // no-issue rationale and hard-blocked under `linkedIssueGateMode === "block"`.
-  return /\b(?:no issue\s*(?:because\b|:)|no linked issue\s*(?:because\b|:)|no ticket\s*(?:because\b|:)|(?:maintenance|docs?[\s-]+only|typo|chore|cleanup)\b)/i.test([pr.title, pr.body ?? ""].join(" "));
+  // `tests?[\s-]+only` extends the same rule to test-only PRs (regression/coverage-only diffs) — parallel
+  // to the docs-only hyphenation fix merged in #1905.
+  return /\b(?:no issue\s*(?:because\b|:)|no linked issue\s*(?:because\b|:)|no ticket\s*(?:because\b|:)|(?:maintenance|docs?[\s-]+only|tests?[\s-]+only|typo|chore|cleanup)\b)/i.test([pr.title, pr.body ?? ""].join(" "));
 }
 
 function hasValidationNote(value: string): boolean {

test/unit/signals-v2.test.ts

@@ -1760,6 +1760,20 @@ describe("hasClearNoIssueRationale docs-only spelling", () => {
   });
 });
 
+describe("hasClearNoIssueRationale test-only spelling", () => {
+  it("recognizes hyphenated and spaced test-only rationales", () => {
+    expect(hasClearNoIssueRationale({ title: "test only: lock regression", body: "" })).toBe(true);
+    expect(hasClearNoIssueRationale({ title: "test-only: lock regression", body: "" })).toBe(true);
+    expect(hasClearNoIssueRationale({ title: "tests-only coverage", body: "" })).toBe(true);
+    expect(hasClearNoIssueRationale({ title: "Add branch classifier", body: "This is a tests only change." })).toBe(true);
+  });
+
+  it("still rejects unrelated PR text that mentions tests without a rationale", () => {
+    expect(hasClearNoIssueRationale({ title: "Add tests for classifier", body: "Adds coverage." })).toBe(false);
+    expect(hasClearNoIssueRationale({ title: "Improve test harness", body: "" })).toBe(false);
+  });
+});
+
 function snapshot(
   id: string,
   repositories: Array<{