feat: search --hop walks FROM_FILE to Person. (#30)

Parser no longer errors; hop 1 returns File, hop 3 reaches Person.
Rebuild writes Leaf-[:FROM_FILE]->File so the walk is not empty
on a fresh index (Gitea #17).

bin/tools/test_kblib.py

@@ -161,6 +161,39 @@ class KblibTest(unittest.TestCase):
         self.assertEqual(stats["total"], 2)
         self.assertEqual(stats["by_root"], {"facts": 1, "info": 1})
 
+    def test_hop_1_returns_file_hop_3_reaches_person(self):
+        """--hop walks FROM_FILE / HAS_VERSION / AUTHORED (Gitea #17)."""
+        import gitimport
+
+        lid = kblib.upsert_leaf(
+            self.conn, text="readme hop fixture", root="info",
+            confidence="confirmed", source="README.md", source_rev="r1",
+            how="test", loc="README.md", type_="reference",
+            embedding=make_emb(0.3),
+        )
+        kblib.link_from_file(self.conn, lid, "README.md", repo="sample-repo")
+        gitimport.index_commits(self.conn, [gitimport.Commit(
+            sha="a1b2c3d",
+            author="Ada Lovelace",
+            email="ada@example.com",
+            date="2026-08-10T12:00:00Z",
+            subject="feat: first commit",
+            files=["README.md"],
+        )], "sample-repo")
+        hop1 = kblib.hop_walk(self.conn, lid, 1)
+        self.assertEqual(len(hop1), 1)
+        self.assertEqual(hop1[0]["label"], "File")
+        self.assertEqual(hop1[0]["name"], "README.md")
+        self.assertEqual(hop1[0]["depth"], 1)
+        hop3 = kblib.hop_walk(self.conn, lid, 3)
+        labels = {n["label"] for n in hop3}
+        self.assertIn("File", labels)
+        self.assertIn("Commit", labels)
+        self.assertIn("Person", labels)
+        person = [n for n in hop3 if n["label"] == "Person"][0]
+        self.assertEqual(person["name"], "Ada Lovelace")
+        self.assertEqual(person["depth"], 3)
+
 
 if __name__ == "__main__":
     unittest.main()