Add bottle size, bourbon list modal, and stat improvements

- Add bottle_size field to User model and UserResponse/UserUpdate schemas
- Settings modal includes bottle size input (shots capacity)
- Community bottles and My Bottle page show fill bar based on bottle size
- Community bottle cards are clickable — opens searchable bourbon list modal
- Add total_shots_added stat to replace duplicate net volume on dashboard
- Reorder dashboard stats: Bourbons Added, Total Poured In, Shots Remaining, Est. Proof
- Theme-matched custom scrollbar (amber on dark)

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

backend/app/routers/entries.py

@@ -25,6 +25,7 @@ def _calc_stats(entries: list[Entry]) -> BottleStats:
 
     return BottleStats(
         total_add_entries=len(adds),
+        total_shots_added=round(total_add_shots, 2),
         current_total_shots=round(current_total, 2),
         estimated_proof=round(estimated_proof, 1) if estimated_proof is not None else None,
     )
@@ -61,9 +62,8 @@ async def create_entry(
         amount_shots=body.amount_shots,
         notes=body.notes,
     )
-    async with db.begin():
-        db.add(entry)
-
+    db.add(entry)
+    await db.commit()
     await db.refresh(entry)
     return entry
 
@@ -81,8 +81,8 @@ async def delete_entry(
     if not entry:
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Entry not found")
 
-    async with db.begin():
-        await db.delete(entry)
+    await db.delete(entry)
+    await db.commit()
 
 
 @router.get("/stats", response_model=BottleStats)