test(snippets): fix the round-trip test's shared kwargs spread

Run 2923: 1 failed, 408 passed. My test bug, not a code one — I spread one
`fields` dict into both compose_body and compose_data, but compose_body takes no
`name` (the name lives in the title). Each serializer now gets its own argument
list.

The migration itself was fine: the integration lane ran 0001→0070 on
pgvector/pg17 green.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLwAaV4DQEmVyn496HnEvt

tests/test_services_snippets.py

@@ -228,19 +228,21 @@ def test_snippet_fields_falls_back_to_the_body_when_data_is_absent():
 def test_data_and_body_round_trip_to_the_same_fields():
     """The two representations must agree — they're written together, and a
     disagreement would make a snippet read one way and query another."""
-    fields = dict(name="debounce", when_to_use="rate-limit a callback",
+    name, when, sig, lang = ("debounce", "rate-limit a callback",
-                  signature="debounce(fn, ms)", language="ts")
+                             "debounce(fn, ms)", "ts")
     locs = [{"repo": "web", "path": "src/util.ts", "symbol": "debounce"}]
-    from_body = s.snippet_fields(_Note(
+    # compose_body takes no `name` — the name lives in the title — so the two
-        title=s.compose_title(fields["name"], fields["when_to_use"]),
+    # serializers get their own argument lists rather than a shared spread.
-        body=s.compose_body(code="const x = 1", locations=locs, **fields),
+    title = s.compose_title(name, when)
-        tags=s.compose_tags(fields["language"]),
+    body = s.compose_body(code="const x = 1", language=lang, signature=sig,
-    ))
+                          when_to_use=when, locations=locs)
+    tags = s.compose_tags(lang)
+
+    from_body = s.snippet_fields(_Note(title=title, body=body, tags=tags))
     from_data = s.snippet_fields(_Note(
-        title=s.compose_title(fields["name"], fields["when_to_use"]),
+        title=title, body=body, tags=tags,
-        body=s.compose_body(code="const x = 1", locations=locs, **fields),
+        data=s.compose_data(name=name, when_to_use=when, signature=sig,
-        tags=s.compose_tags(fields["language"]),
+                            language=lang, locations=locs),
-        data=s.compose_data(locations=locs, **fields),
     ))
     for key in ("name", "when_to_use", "signature", "language", "locations",
                 "repo", "path", "symbol", "code"):