fix: type the lists and returns mypy flagged

The data tree record carries the needed flag since 072380c26, and
the manifest test still built the three-part one. profile_sync's triage
lists and _emit's returns, site_insights' GoatCounter answers and
make_demo's blocks are annotated, and the baseline loses the entry
that no longer occurs.

scripts/make_demo.py

@@ -89,7 +89,8 @@ VIDEO_FPS = 25
 def game_bytes(name: str) -> bytes:
     """Bytes of a game no catalog names, the same on every run."""
     seed = hashlib.sha256(name.encode("utf-8")).digest()
-    blocks, counter = [], 0
+    blocks: list[bytes] = []
+    counter = 0
     while len(blocks) * 32 < GAME_BYTES:
         blocks.append(hashlib.sha256(seed + counter.to_bytes(4, "big")).digest())
         counter += 1