Distinguish a pending-only balance from a truly insufficient one (B-37)

request_withdrawal validated against confirmed UTXOs only and answered
a flat insufficient_balance even when the requested amount was covered
by the pending-inclusive balance the UI actually shows (unconfirmed
change from a recent bet/withdrawal) — contradicting what the user was
looking at on screen. Raise balance_pending_confirmation instead when
compute_pending_balance covers the amount, carrying the pending sats
in params, with its error.* string in all 7 languages.

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

app/static/i18n.js

@@ -121,6 +121,7 @@ const TRANSLATIONS = {
     'error.round_closing': 'The current round is closing, please try again shortly.',
     'error.already_betting': 'You already have an active bet in the current round.',
     'error.insufficient_balance': 'Insufficient balance.',
+    'error.balance_pending_confirmation': 'You have {pending_plm} PLM pending confirmation — it is not spendable yet.',
     'error.amount_below_network_fee': 'The amount is too small to cover the network fee.',
     'error.invalid_address': 'Not a valid PLM address (it must start with plm1q…).',
     'error.amount_below_minimum': 'The minimum withdrawal amount is {minimum_plm} PLM.',
@@ -259,6 +260,7 @@ const TRANSLATIONS = {
     'error.round_closing': 'Il round corrente si sta chiudendo, riprova tra poco.',
     'error.already_betting': 'Hai già una bet attiva nel round corrente.',
     'error.insufficient_balance': 'Saldo insufficiente.',
+    'error.balance_pending_confirmation': 'Hai {pending_plm} PLM in attesa di conferma — non ancora disponibili per la spesa.',
     'error.amount_below_network_fee': "L'importo è troppo basso per coprire la fee di rete.",
     'error.invalid_address': 'Indirizzo PLM non valido (deve iniziare con plm1q…).',
     'error.amount_below_minimum': "L'importo minimo di prelievo è {minimum_plm} PLM.",
@@ -397,6 +399,7 @@ const TRANSLATIONS = {
     'error.round_closing': 'La ronda actual se está cerrando, inténtalo de nuevo en un momento.',
     'error.already_betting': 'Ya tienes una apuesta activa en la ronda actual.',
     'error.insufficient_balance': 'Saldo insuficiente.',
+    'error.balance_pending_confirmation': 'Tienes {pending_plm} PLM pendientes de confirmación — todavía no se pueden gastar.',
     'error.amount_below_network_fee': 'El importe es demasiado pequeño para cubrir la comisión de red.',
     'error.invalid_address': 'Dirección PLM no válida (debe empezar por plm1q…).',
     'error.amount_below_minimum': 'El importe mínimo de retiro es {minimum_plm} PLM.',
@@ -535,6 +538,7 @@ const TRANSLATIONS = {
     'error.round_closing': 'Le round en cours est en train de se fermer, réessayez dans un instant.',
     'error.already_betting': 'Vous avez déjà une mise active dans le round en cours.',
     'error.insufficient_balance': 'Solde insuffisant.',
+    'error.balance_pending_confirmation': 'Vous avez {pending_plm} PLM en attente de confirmation — pas encore disponibles.',
     'error.amount_below_network_fee': 'Le montant est trop faible pour couvrir les frais de réseau.',
     'error.invalid_address': 'Adresse PLM invalide (elle doit commencer par plm1q…).',
     'error.amount_below_minimum': 'Le montant minimum de retrait est de {minimum_plm} PLM.',
@@ -673,6 +677,7 @@ const TRANSLATIONS = {
     'error.round_closing': 'Die laufende Runde wird gerade geschlossen, bitte versuche es gleich erneut.',
     'error.already_betting': 'Du hast bereits eine aktive Wette in der laufenden Runde.',
     'error.insufficient_balance': 'Nicht genügend Guthaben.',
+    'error.balance_pending_confirmation': 'Sie haben {pending_plm} PLM, die noch auf Bestätigung warten — noch nicht verfügbar.',
     'error.amount_below_network_fee': 'Der Betrag ist zu klein, um die Netzwerkgebühr zu decken.',
     'error.invalid_address': 'Keine gültige PLM-Adresse (sie muss mit plm1q… beginnen).',
     'error.amount_below_minimum': 'Der Mindestauszahlungsbetrag beträgt {minimum_plm} PLM.',
@@ -811,6 +816,7 @@ const TRANSLATIONS = {
     'error.round_closing': 'Текущий раунд закрывается, повторите попытку чуть позже.',
     'error.already_betting': 'У вас уже есть активная ставка в текущем раунде.',
     'error.insufficient_balance': 'Недостаточно средств.',
+    'error.balance_pending_confirmation': 'У вас есть {pending_plm} PLM, ожидающих подтверждения — они пока недоступны для расходования.',
     'error.amount_below_network_fee': 'Сумма слишком мала, чтобы покрыть комиссию сети.',
     'error.invalid_address': 'Некорректный адрес PLM (он должен начинаться с plm1q…).',
     'error.amount_below_minimum': 'Минимальная сумма вывода — {minimum_plm} PLM.',
@@ -949,6 +955,7 @@ const TRANSLATIONS = {
     'error.round_closing': '当前回合正在结束，请稍后重试。',
     'error.already_betting': '你在当前回合已有一笔有效下注。',
     'error.insufficient_balance': '余额不足。',
+    'error.balance_pending_confirmation': '您有 {pending_plm} PLM 待确认 —— 尚不可用于支出。',
     'error.amount_below_network_fee': '金额太小，不足以支付网络手续费。',
     'error.invalid_address': 'PLM 地址无效（必须以 plm1q… 开头）。',
     'error.amount_below_minimum': '最低提现金额为 {minimum_plm} PLM。',

app/withdrawals/service.py

@@ -9,7 +9,7 @@ from app.electrum.client import ElectrumClient
 from app.rounds.config import get_round_config
 from app.rounds.events import broadcaster
 from app.wallet.address import is_valid_plm_address
-from app.wallet.balance import recompute_balance
+from app.wallet.balance import compute_pending_balance, recompute_balance
 from app.wallet.hd import derive_user_key
 from app.wallet.psbt_builder import (
     BuiltTransaction,
@@ -56,7 +56,22 @@ async def request_withdrawal(
             select(UtxoEvent).where(UtxoEvent.user_id == user.id, UtxoEvent.spent_txid.is_(None))
         )
     ).all()
-    if sum(u.amount_sats for u in unspent) < amount_sats:
+    confirmed_sats = sum(u.amount_sats for u in unspent)
+    if confirmed_sats < amount_sats:
+        # B-37: cached_balance_sats (== confirmed_sats here) can understate the real
+        # balance by a whole unconfirmed change output right after a bet/withdrawal —
+        # the UI shows pending_balance_sats instead (compute_pending_balance), which
+        # can cover an amount this check would otherwise reject as flatly
+        # "insufficient". Distinguish "you don't have the money" from "your money
+        # hasn't confirmed yet" so the error doesn't contradict what the user is
+        # looking at on screen.
+        pending_inclusive_sats, has_pending = await compute_pending_balance(session, user)
+        if has_pending and pending_inclusive_sats >= amount_sats:
+            raise WithdrawalError(
+                "balance_pending_confirmation",
+                "the requested amount is covered by your pending balance, which has not confirmed yet",
+                pending_sats=pending_inclusive_sats - confirmed_sats,
+            )
         raise WithdrawalError("insufficient_balance", "insufficient balance", required_sats=amount_sats)
 
     user_key = derive_user_key(user.derivation_index)