feat(retrieval): a menu line is a name, its kind and System, and the whole passage that matched (#4364)

Injected lines rendered a snippet's or lesson's title, which carries its
whole trigger by construction (the embedding shape) and ran past 1,500
characters -- again on every `seen` repeat. The passage under a line was
cut to 200 chars from the middle, keeping its head (the title again) and
losing where the match was.

Now, on both the prompt menu and the write-path prior-art menu:
- the line shows the record's NAME (snippet data.name / lesson subject),
  with its kind and System (`[issue (done) · Plugin & hooks]`);
- the passage is the whole matched chunk, title prefix stripped, on one
  line so the blockquote holds; a title-only match hands over the trigger;
- a `seen` record is a one-line pointer to what is already in context.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/services/systems.py

@@ -310,6 +310,39 @@ async def list_record_systems(user_id: int, note_id: int) -> list[System]:
         return list(result.scalars().all())
 
 
+async def system_names_for(note_ids: set[int]) -> dict[int, list[str]]:
+    """{note_id: [system name, …]} in one query, for records ALREADY read.
+
+    For decorating a result set the caller was allowed to see — an injected
+    menu line says which part of the project a record is about, so the reader
+    can place it without opening it (#4364). No access check here for that
+    reason: the ids come from a search that applied one, and a system name is
+    metadata of the record, not a record of its own.
+
+    Fails soft, like `access.owner_names_for`: a menu without its system labels
+    is a cosmetic downgrade, and failing the whole injection over one is not.
+    """
+    if not note_ids:
+        return {}
+    try:
+        async with async_session() as session:
+            rows = (
+                await session.execute(
+                    select(RecordSystem.note_id, System.name)
+                    .join(System, System.id == RecordSystem.system_id)
+                    .where(RecordSystem.note_id.in_(note_ids), System.deleted_at.is_(None))
+                    .order_by(System.order_index.asc(), System.name.asc())
+                )
+            ).all()
+    except Exception:
+        logger.warning("System-name lookup failed; menu lines go unlabelled", exc_info=True)
+        return {}
+    out: dict[int, list[str]] = {}
+    for note_id, name in rows:
+        out.setdefault(int(note_id), []).append(name)
+    return out
+
+
 async def list_records_for_system(
     user_id: int, system_id: int, kind: str | None = None, open_only: bool = False
 ) -> list[Note]: