fix(gate-46): a fragment copied from a real GitHub link did not match the alias it was copied from

hydra-gates/scripts/lib/check_spec_anchors.py

@@ -246,7 +246,24 @@ def has_anchor(md_path: str, fragment: str) -> bool:
     """True when *fragment* names a heading or task item in *md_path*."""
     frag_slug = slugify(fragment)
     frag_alt = slugify(re.sub(r'^task-', '', fragment))
-    frags = (frag_slug, frag_alt)
+    # The fragment VERBATIM, alongside its slugified forms.
+    #
+    # `heading_aliases` already produces both spellings of a heading — the
+    # kebab one and the one GitHub actually publishes — but the fragment was
+    # being pushed through `slugify()` first, and that rewrites `_` to `-`.
+    # A tag copied from a real GitHub link therefore stopped matching the
+    # gh alias it was copied FROM:
+    #
+    #   heading   ### Requirement: Trace-scoped call correlation via
+    #                 call_log.sessionId (REQ-011)
+    #   gh alias  …-via-call_logsessionid-req-011      ← what GitHub links to
+    #   fragment  …-via-call_logsessionid-req-011      ← what the author wrote
+    #   slugified …-via-call-logsessionid-req-011      ← what was compared
+    #
+    # which matches neither alias: not the gh one (underscore rewritten) and
+    # not the kebab one (`call-log-sessionid`, split at the underscore).
+    # Reported as "anchor not found" on a tag whose link works.
+    frags = (frag_slug, frag_alt, fragment.lower())
     pos_m = re.fullmatch(r'(?:task-)?(\d+)', fragment)
     positional = int(pos_m.group(1)) if pos_m else None
     item_count = 0

hydra-gates/scripts/lib/test_check_spec_anchors.py

@@ -379,6 +379,52 @@ def test_a_wholly_invented_fragment_is_still_reported(self):
         self.assertIn("anchor not found", findings[0])
 
 
+class FragmentCopiedFromAGitHubLink(unittest.TestCase):
+    """A tag copied from a real GitHub link must resolve.
+
+    ``heading_aliases`` already emits both spellings of a heading — the kebab
+    one and the one GitHub publishes — but the FRAGMENT was pushed through
+    ``slugify()`` before comparison, and that rewrites ``_`` to ``-``. So a
+    fragment matched neither alias: not the gh one (its underscore had been
+    rewritten) and not the kebab one (which splits at the underscore).
+    Observed on openconnector ``SynchronizationService`` (2026-08-07).
+    """
+
+    MD = (
+        "# HTTP call engine\n\n"
+        "### Requirement: Trace-scoped call correlation via call_log.sessionId (REQ-011)\n\n"
+        "Body.\n"
+    )
+
+    def test_the_github_spelling_resolves(self):
+        # What GitHub links to: underscore kept, dot dropped.
+        self.assertTrue(_anchor(
+            self.MD,
+            "requirement-trace-scoped-call-correlation-via-call_logsessionid-req-011",
+        ))
+
+    def test_the_kebab_spelling_still_resolves(self):
+        self.assertTrue(_anchor(
+            self.MD,
+            "requirement-trace-scoped-call-correlation-via-call-log-sessionid-req-011",
+        ))
+
+    def test_a_near_miss_does_not_resolve(self):
+        # The control. Accepting the raw fragment must not become "accept any
+        # fragment that shares a prefix" — this one names a heading the file
+        # does not have.
+        self.assertFalse(_anchor(
+            self.MD,
+            "requirement-trace-scoped-call-correlation-via-call_logrequestid-req-011",
+        ))
+
+    def test_an_underscore_fragment_against_a_file_without_it_does_not_resolve(self):
+        self.assertFalse(_anchor(
+            "# Other\n\n### Requirement: Something else entirely (REQ-012)\n",
+            "requirement-trace-scoped-call-correlation-via-call_logsessionid-req-011",
+        ))
+
+
 class GateIsNotBlind(unittest.TestCase):
     """One consolidated demonstration that the gate still has teeth.