test: check the compact samples, which nothing was checking

The two text formats spell a check name differently — the default output
prints the kebab-case name, --compact prints the config key — so a sample
of one cannot be validated against the other. The existing guard only
matches the default format, which meant every --compact sample on the
site was checked by nothing at all.

That is the same blind spot that let a pre-2.13 sample sit unnoticed in
the troubleshooting page: the sample was stale in a format the guard
could not see, and every test still passed. Fixing that one sample did
not close the hole it came through.

Two samples were uncovered, in example.md and rules.md — one indented
inside a content tab, one not, so the pattern allows leading whitespace.
Verified by breaking one deliberately: the guard names the file and both
spellings, rather than only going red.

This also decides what happens if commit-check#528 reconciles the two
formats upstream. Today that would quietly leave both samples wrong;
now docs-sync fails and says which lines to rewrite.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01U9zFxq8V4qxG4aMzJhGBFn

Author: claude

tests/docs_sync_test.py

@@ -32,6 +32,10 @@ def _read_doc(name: str) -> str:
 #: A pasted failure line, e.g. ``CC003 subject-imperative check failed ==> ...``
 _SAMPLE_FAILURE = re.compile(r"(CC\d{3}) (\S+) check failed ==>")
 
+#: A pasted ``--compact`` line, e.g. ``[FAIL] CC003 subject_imperative: ...``.
+#: Indented, because these samples sit inside content tabs.
+_COMPACT_FAILURE = re.compile(r"^\s*\[FAIL\] (CC\d{3}) ([^:\s]+):", re.M)
+
 
 def _rule_section(content: str, rule_id: str) -> str:
     """Return just the part of the rules page belonging to one rule."""
@@ -83,6 +87,33 @@ def test_sample_output_matches_what_the_tool_prints(self):
                     )
         assert not stale, "sample output is out of date:\n  " + "\n  ".join(stale)
 
+    def test_compact_sample_output_matches_what_the_tool_prints(self):
+        """Pasted ``--compact`` output names rules the way that format does.
+
+        The two text formats spell a check differently: the default output
+        prints the kebab-case name, and ``--compact`` prints the config key.
+        A sample of one therefore cannot be validated against the other, and
+        the guard above only matches the default format — so the compact
+        samples were checked by nothing at all. That is the blind spot that
+        let a pre-2.13 sample sit unnoticed in the troubleshooting page.
+
+        If the two formats are ever reconciled (see commit-check#528), this
+        is what will point at the samples that need rewriting.
+        """
+        by_id = {entry.rule_id: entry for entry in ALL_RULES}
+        stale = []
+        for page in DOCS.rglob("*.md"):
+            for rule_id, printed in _COMPACT_FAILURE.findall(page.read_text("utf-8")):
+                entry = by_id.get(rule_id)
+                if entry and printed != entry.check:
+                    stale.append(
+                        f"{page.relative_to(DOCS)}: {rule_id} shown as "
+                        f"'{printed}', --compact prints '{entry.check}'"
+                    )
+        assert not stale, (
+            "compact sample output is out of date:\n  " + "\n  ".join(stale)
+        )
+
     def test_every_rule_explains_itself(self):
         """Each rule section must answer what it does and why it matters."""
         content = _read_doc("rules.md")