feat: add limit/pagination to cardpositions endpoint (#142)

Closes #142

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/routers_v2/cardpositions.py

@@ -51,6 +51,7 @@ async def get_card_positions(
     cardset_id: list = Query(default=None),
     short_output: Optional[bool] = False,
     sort: Optional[str] = "innings-desc",
+    limit: int = 100,
 ):
     all_pos = (
         CardPosition.select()
@@ -86,6 +87,9 @@ async def get_card_positions(
     elif sort == "range-asc":
         all_pos = all_pos.order_by(CardPosition.range, CardPosition.id)
 
+    limit = max(0, min(limit, 500))
+    all_pos = all_pos.limit(limit)
+
     return_val = {
         "count": all_pos.count(),
         "positions": [model_to_dict(x, recurse=not short_output) for x in all_pos],