fix(expand,setup): append behavioral findings to sections 02-behavioral-profile.md actually has (#520)

Both commands told the model to add to "Strongest Behavioral Traits" and
"How I Work Best" / "How [Candidate] Works Best" while also saying "match
existing structure", but the shipped file's headings are "Strongest
Behaviors" and "How You Work Best", so an inferred trait either opened a
duplicate near-identical section or was dropped.

The companion to #519, which fixed the same drift in /reset's skeleton.
Both bullets now name the shipped headings, and a derived test in each
command's suite reads the quoted section names and requires each to be a
## heading of the shipped file; both fail on master.

tests/test_setup_command.py

@@ -10,6 +10,7 @@ on the drafter noticing. A real user (#420) ran `/setup` and then hand-edited bo
 files to close the gap.
 """
 import os
+import re
 import unittest
 from pathlib import Path
 
@@ -90,6 +91,35 @@ class TemplatesStillCarryThePlaceholders(unittest.TestCase):
         self.assertIn("\\signature{[YOUR_NAME]}", text)
 
 
+class SetupPathAWritesIntoSectionsTheShippedFilesHave(unittest.TestCase):
+    """Step A7 named 02-behavioral-profile.md sections that do not exist.
+
+    "Strongest Behavioral Traits" and "How [Candidate] Works Best" are not
+    headings in the shipped file ("Strongest Behaviors", "How You Work Best"
+    are), so the "add only to these sections" rule pointed at nothing. The
+    section names are read from the bullet and checked against the file's
+    `##` headings, with the placeholder-free spelling required: a reader
+    cannot match "[Candidate]" against a heading.
+    """
+
+    def test_behavioral_profile_bullet_names_real_headings(self):
+        text = COMMAND.read_text(encoding="utf-8")
+        bullet = next(
+            line for line in text.splitlines()
+            if line.startswith("- **`02-behavioral-profile.md`:**")
+        )
+        quoted = re.findall(r'"([^"]+)"', bullet)
+        self.assertTrue(quoted, "the 02-behavioral-profile bullet must name its target sections")
+        headings = {
+            line[3:].strip()
+            for line in (SKILL_DIR / "02-behavioral-profile.md").read_text(encoding="utf-8").splitlines()
+            if line.startswith("## ")
+        }
+        for name in quoted:
+            with self.subTest(section=name):
+                self.assertIn(name, headings, f"02-behavioral-profile.md has no '## {name}' heading")
+
+
 class SetupPathAProjectsIngestion(unittest.TestCase):
     """Guards for /setup Path A document ingestion of documents/projects/."""