fix: address review feedback (#52)

Guard bulk ID queries against empty lists to prevent PostgreSQL
syntax error (WHERE id IN ()) when batch POST endpoints receive
empty request bodies.

Affected endpoints:
- POST /api/v3/transactions
- POST /api/v3/results
- POST /api/v3/schedules
- POST /api/v3/battingstats

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

app/routers_v3/battingstats.py

@@ -383,11 +383,15 @@ async def post_batstats(s_list: BatStatList, token: str = Depends(oauth2_scheme)
 
     all_team_ids = list(set(x.team_id for x in s_list.stats))
     all_player_ids = list(set(x.player_id for x in s_list.stats))
-    found_team_ids = set(
-        t.id for t in Team.select(Team.id).where(Team.id << all_team_ids)
+    found_team_ids = (
+        set(t.id for t in Team.select(Team.id).where(Team.id << all_team_ids))
+        if all_team_ids
+        else set()
     )
-    found_player_ids = set(
-        p.id for p in Player.select(Player.id).where(Player.id << all_player_ids)
+    found_player_ids = (
+        set(p.id for p in Player.select(Player.id).where(Player.id << all_player_ids))
+        if all_player_ids
+        else set()
     )
 
     for x in s_list.stats:

app/routers_v3/results.py

@@ -164,8 +164,10 @@ async def post_results(result_list: ResultList, token: str = Depends(oauth2_sche
         set(x.awayteam_id for x in result_list.results)
         | set(x.hometeam_id for x in result_list.results)
     )
-    found_team_ids = set(
-        t.id for t in Team.select(Team.id).where(Team.id << all_team_ids)
+    found_team_ids = (
+        set(t.id for t in Team.select(Team.id).where(Team.id << all_team_ids))
+        if all_team_ids
+        else set()
     )
 
     for x in result_list.results:

app/routers_v3/schedules.py

@@ -149,8 +149,10 @@ async def post_schedules(sched_list: ScheduleList, token: str = Depends(oauth2_s
         set(x.awayteam_id for x in sched_list.schedules)
         | set(x.hometeam_id for x in sched_list.schedules)
     )
-    found_team_ids = set(
-        t.id for t in Team.select(Team.id).where(Team.id << all_team_ids)
+    found_team_ids = (
+        set(t.id for t in Team.select(Team.id).where(Team.id << all_team_ids))
+        if all_team_ids
+        else set()
     )
 
     for x in sched_list.schedules:

app/routers_v3/transactions.py

@@ -147,11 +147,15 @@ async def post_transactions(
         set(x.oldteam_id for x in moves.moves) | set(x.newteam_id for x in moves.moves)
     )
     all_player_ids = list(set(x.player_id for x in moves.moves))
-    found_team_ids = set(
-        t.id for t in Team.select(Team.id).where(Team.id << all_team_ids)
+    found_team_ids = (
+        set(t.id for t in Team.select(Team.id).where(Team.id << all_team_ids))
+        if all_team_ids
+        else set()
     )
-    found_player_ids = set(
-        p.id for p in Player.select(Player.id).where(Player.id << all_player_ids)
+    found_player_ids = (
+        set(p.id for p in Player.select(Player.id).where(Player.id << all_player_ids))
+        if all_player_ids
+        else set()
     )
 
     for x in moves.moves: