Advertise the jackpot that will actually be paid (B-65)

participant_count and jackpot_sats were computed over every round_participants
row, while the draw only picks from confirmed participants and the payout only
spends their sats. So the advertised jackpot could exceed the one paid out, and a
player whose bet was later abandoned appeared in the count and then vanished
again.

Counting only confirmed rows would have fixed the arithmetic and broken something
else: the player who just bet would see neither themselves nor their money for a
whole block. So this is the same confirmed/in-flight split the balance already
exposes (balance_sats vs pending_balance_sats): participant_count and
jackpot_sats are now the confirmed, authoritative figures, and
pending_participant_count/pending_jackpot_sats/has_pending_bets report what is in
flight — inclusive figures, not deltas, matching the balance pair's convention.

/'s round card shows the confirmed numbers big and the difference as an amber
"+N in attesa" suffix, reusing .balance-pending's colour for the same "not
settled yet" meaning. The two new spans render from server data through t(), so
they carry no data-i18n and onLanguageChange() repaints them from the last
response — the one-mechanism-per-element rule. Both strings are in all 7
languages.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/unit/test_rounds_route.py

@@ -134,6 +134,64 @@ async def test_jackpot_comes_from_the_participants_actual_bets(client):
     assert body["jackpot_sats"] == (999_800_000 * 2) * 70 // 100
 
 
+async def test_advertised_jackpot_covers_only_the_bets_that_will_be_paid(client):  # B-65
+    """The draw picks from confirmed participants and the payout spends only their
+    sats, so counting every participant row advertised a jackpot bigger than the one
+    that would actually be paid — and let a player appear in the count and then
+    vanish again if their bet was abandoned. The confirmed figures are the headline
+    ones; what's in flight is reported alongside, never folded in."""
+    from app.db.models import Round, RoundConfig, RoundParticipant
+
+    ac, session_factory = client
+
+    async with session_factory() as session:
+        session.add(RoundConfig(fee_address="", bet_amount_sats=1_000_000_000))
+        session.add(Round(id=60, status="open"))
+        await session.flush()
+        session.add(
+            RoundParticipant(round_id=60, user_id=1, bet_amount_sats=999_800_000, bet_txid="a", status="confirmed")
+        )
+        # One mid-broadcast and one written but not yet broadcast: both in flight,
+        # neither drawn from nor spent by the payout as things stand.
+        session.add(
+            RoundParticipant(round_id=60, user_id=2, bet_amount_sats=999_800_000, bet_txid="b", status="broadcast")
+        )
+        session.add(
+            RoundParticipant(round_id=60, user_id=3, bet_amount_sats=999_800_000, bet_txid="c", status="building")
+        )
+        await session.commit()
+
+    body = (await ac.get("/rounds/current")).json()
+
+    assert body["participant_count"] == 1
+    assert body["jackpot_sats"] == 999_800_000 * 70 // 100
+    # Inclusive, like pending_balance_sats — not a delta.
+    assert body["pending_participant_count"] == 3
+    assert body["pending_jackpot_sats"] == (999_800_000 * 3) * 70 // 100
+    assert body["has_pending_bets"] is True
+
+
+async def test_no_pending_bets_reported_once_every_bet_has_confirmed(client):  # B-65
+    from app.db.models import Round, RoundConfig, RoundParticipant
+
+    ac, session_factory = client
+
+    async with session_factory() as session:
+        session.add(RoundConfig(fee_address="", bet_amount_sats=1_000_000_000))
+        session.add(Round(id=61, status="open"))
+        await session.flush()
+        session.add(
+            RoundParticipant(round_id=61, user_id=1, bet_amount_sats=999_800_000, bet_txid="a", status="confirmed")
+        )
+        await session.commit()
+
+    body = (await ac.get("/rounds/current")).json()
+
+    assert body["has_pending_bets"] is False
+    assert body["pending_participant_count"] == body["participant_count"] == 1
+    assert body["pending_jackpot_sats"] == body["jackpot_sats"]
+
+
 async def test_draw_waiting_since_is_exposed_only_while_drawing(client):
     """B-36: the "drawing" wait on a future block has no timeout, so the frontend
     needs draw_waiting_since to show "still waiting" instead of implying a bounded