fix: keep the skip sentence short

Drop the config section from the verdict sentence so the common bot
case reads "Skipped because author dependabot[bot] is in
ignore_authors." once; the per-line reasons keep the section. Accept
the CLI's new optional reason key in the real-binary contract test.

Author: shenxianpeng

main.py

@@ -1053,10 +1053,16 @@ def _skip_count(results: list[ScopeResult]) -> int:
 def _skip_reasons(results: list[ScopeResult]) -> str:
     """One sentence naming why checks were skipped, or ``""`` if unknown.
 
-    The verdict line is all most readers see; the per-scope reasons sit in
-    a collapsed block. Each distinct reason is named once, in order.
+    The verdict line is all most readers see, so it stays short: the config
+    section is dropped ("[commit].ignore_authors" and "[branch].ignore_authors"
+    both read "ignore_authors"), which folds the usual bot case into one
+    reason. The per-scope lines in the collapsed block keep the section.
     """
-    reasons = list(dict.fromkeys(s.skip_reason for s in results if s.skip_reason))
+    reasons = list(
+        dict.fromkeys(
+            re.sub(r"\[\w+\]\.", "", s.skip_reason) for s in results if s.skip_reason
+        )
+    )
     return f"Skipped because {'; '.join(reasons)}." if reasons else ""
 
 
@@ -1240,8 +1246,7 @@ def _scope_value(scope: ScopeResult, max_len: int = 60) -> str:
 #
 #   ⊘ **All 5 checks skipped** — nothing was validated
 #
-#   Skipped because author dependabot[bot] is in [commit].ignore_authors;
-#   author dependabot[bot] is in [branch].ignore_authors.
+#   Skipped because author dependabot[bot] is in ignore_authors.
 #
 #   ```text
 #   Commit message

main_test.py

@@ -2778,7 +2778,7 @@ def test_skip_reason_is_shown_on_the_scope_and_under_the_verdict(self):
         body = main.render_report(results)
         self.assertIn(
             "⊘ **All 3 checks skipped** — nothing was validated\n\n"
-            f"Skipped because {commit}; {branch}.\n",
+            "Skipped because author dependabot[bot] is in ignore_authors.\n",
             body,
         )
         self.assertIn(f"  ⊘ PR title (skipped: {commit})", body)
@@ -2789,7 +2789,8 @@ def test_skip_reason_follows_a_partial_skip_verdict(self):
         results = [pass_scope("PR title"), skip_scope("Branch", reason=reason)]
         body = main.render_report(results)
         self.assertIn(
-            f"✅ **1 of 2 checks passed**, 1 skipped\n\nSkipped because {reason}.\n",
+            "✅ **1 of 2 checks passed**, 1 skipped\n\n"
+            "Skipped because author dependabot[bot] is in ignore_authors.\n",
             body,
         )
 
@@ -2798,14 +2799,20 @@ def test_skip_reason_reaches_the_step_log(self):
         with patch("sys.stdout", new_callable=io.StringIO) as out:
             main.render_step_log([skip_scope("PR title", reason=reason)])
         self.assertIn(f"  ⊘ PR title (skipped: {reason})", out.getvalue())
-        self.assertIn(f"Skipped because {reason}.", out.getvalue())
+        self.assertIn(
+            "Skipped because author dependabot[bot] is in ignore_authors.",
+            out.getvalue(),
+        )
 
     def test_skip_reason_follows_a_partial_skip_in_the_step_log(self):
         reason = "author dependabot[bot] is in [branch].ignore_authors"
         results = [pass_scope("PR title"), skip_scope("Branch", reason=reason)]
         with patch("sys.stdout", new_callable=io.StringIO) as out:
             main.render_step_log(results)
-        self.assertIn(f"Skipped because {reason}.", out.getvalue())
+        self.assertIn(
+            "Skipped because author dependabot[bot] is in ignore_authors.",
+            out.getvalue(),
+        )
 
     def test_a_passing_scope_has_no_skip_reason(self):
         self.assertEqual(pass_scope("Branch", value="main").skip_reason, "")
@@ -3216,6 +3223,8 @@ def test_step_log_all_skipped_claims_no_pass(self):
     "fix",
     "docs_url",
 }
+#: Keys newer CLIs add on top: ``reason`` says why a check was skipped.
+OPTIONAL_CHECK_KEYS = {"reason"}
 STATUSES = {"pass", "fail", "warn", "skip"}
 
 
@@ -3278,7 +3287,8 @@ def _run(self, message: str) -> tuple[int, dict]:
         self.assertIn("checks", data)
         self.assertTrue(data["checks"], "CLI reported no checks")
         for check in data["checks"]:
-            self.assertEqual(set(check), CHECK_KEYS, check)
+            self.assertLessEqual(CHECK_KEYS, set(check), check)
+            self.assertLessEqual(set(check), CHECK_KEYS | OPTIONAL_CHECK_KEYS, check)
             self.assertIn(check["status"], STATUSES, check)
             self.assertRegex(check["rule_id"], r"^CC\d{3}$")
             self.assertTrue(