Add draw_animation_seconds config and expose winner info during a round

RoundConfig gains draw_animation_seconds (default 20) — the minimum
time the frontend's "estrazione in corso" animation plays before
revealing a winner. It's purely a UI cue: the real draw still waits for
a confirmed block for its entropy (rounds/scheduler.py), which usually
takes much longer than this value, so it only ever extends the
animation, never truncates the real wait.

GET /rounds/current now also returns draw_animation_seconds,
winner_user_id and winner_amount_sats (all populated once the
scheduler sets them on the round, i.e. from "paying_out" onward) so a
client can determine and reveal the outcome. GET /users/me now returns
the user's own id, needed client-side to compare against winner_user_id.

Admin config CRUD refactored to a shared field tuple (_CONFIG_FIELDS)
instead of repeating the same 7-then-8 field list three times.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/api/routes/admin.py

@@ -20,6 +20,18 @@ async def require_admin(x_admin_token: str = Header(default="")) -> None:
         raise HTTPException(status.HTTP_403_FORBIDDEN, "invalid admin token")
 
 
+_CONFIG_FIELDS = (
+    "fee_address",
+    "bet_amount_sats",
+    "round_duration_seconds",
+    "round_cooldown_seconds",
+    "min_amount_sats",
+    "fee_rate_sat_vb",
+    "rbf_timeout_seconds",
+    "draw_animation_seconds",
+)
+
+
 class RoundConfigResponse(BaseModel):
     fee_address: str
     bet_amount_sats: int
@@ -28,6 +40,7 @@ class RoundConfigResponse(BaseModel):
     min_amount_sats: int
     fee_rate_sat_vb: int
     rbf_timeout_seconds: int
+    draw_animation_seconds: int
 
 
 class RoundConfigUpdate(BaseModel):
@@ -38,18 +51,11 @@ class RoundConfigUpdate(BaseModel):
     min_amount_sats: int | None = None
     fee_rate_sat_vb: int | None = None
     rbf_timeout_seconds: int | None = None
+    draw_animation_seconds: int | None = None
 
 
 def _config_response(config) -> RoundConfigResponse:
-    return RoundConfigResponse(
-        fee_address=config.fee_address,
-        bet_amount_sats=config.bet_amount_sats,
-        round_duration_seconds=config.round_duration_seconds,
-        round_cooldown_seconds=config.round_cooldown_seconds,
-        min_amount_sats=config.min_amount_sats,
-        fee_rate_sat_vb=config.fee_rate_sat_vb,
-        rbf_timeout_seconds=config.rbf_timeout_seconds,
-    )
+    return RoundConfigResponse(**{field: getattr(config, field) for field in _CONFIG_FIELDS})
 
 
 @router.get("/config", response_model=RoundConfigResponse, dependencies=[Depends(require_admin)])
@@ -64,15 +70,7 @@ async def update_config(
     body: RoundConfigUpdate, session: AsyncSession = Depends(get_session)
 ) -> RoundConfigResponse:
     config = await get_round_config(session)
-    for field in (
-        "fee_address",
-        "bet_amount_sats",
-        "round_duration_seconds",
-        "round_cooldown_seconds",
-        "min_amount_sats",
-        "fee_rate_sat_vb",
-        "rbf_timeout_seconds",
-    ):
+    for field in _CONFIG_FIELDS:
         value = getattr(body, field)
         if value is not None:
             setattr(config, field, value)