Fix money-safety bugs in economy (heist, blackjack, bail)

Multi-agent audit of the money-moving economy modules surfaced three
confirmed correctness bugs. All three are fixed here with regression tests.

heist (core/economy/heist.py):
- `house = await get_user(house.HOUSE_ID)` shadowed the imported `house`
  module for the whole function, so `house.HOUSE_ID` raised UnboundLocalError
  on every successful heist (win payout was entirely dead) and on the
  fail-path compensation branch. Rename the local to `house_rec`.
- Un-shadowing exposed a latent mint: the pot was floored at 300 but the
  house was debited only min(total, balance), so a poor house paid out more
  than it lost. Cap the pot at the balance and debit exactly what is paid
  (house debit == sum of payouts). No mint, no leak.
- Add the missing `_is_jailed` import (do_heist_check referenced it unimported).

blackjack (commands/economy_games_commands.py):
- Button callbacks had no reentrancy guard; discord.py dispatches each click
  as its own task, so double-clicking Stand within the dealer-reveal window
  paid out twice (mint), and double-clicking Double/Split deducted the extra
  bet twice. Add a synchronous `_busy` guard (matching the existing RpsGame
  idiom) on all four callbacks plus a `_resolved` idempotency flag on
  settlement, so a game can only pay out once.

bail (core/economy/jail.py, commands/economy_extra_commands.py):
- do_bail only checked balance, never jail state; a double-click or a stale
  BailView from a re-run /jailbreak charged bail twice, destroying coins (bail
  is a pure sink). Make do_bail a no-op when the user is not jailed, and add a
  UI reentrancy guard + "already free" message.

Tests: 47 passed (4 new regression tests covering heist coin-conservation and
bail idempotency).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

core/economy/jail.py

@@ -50,6 +50,12 @@ async def do_bail(user_id: int) -> dict:
     """Charge bail fine after exhausting jailbreak rolls and free the user.
     Fine = 20-30% of current balance, floored at 350. If balance < 350, stay jailed."""
     user = await get_user(user_id)
+    # Idempotency guard: only an actively-jailed user can be charged bail. The
+    # first successful call clears jailed_until, so a rapid second click or a
+    # stale BailView from a re-run /jailbreak becomes a no-op instead of a
+    # second fine (bail is a pure sink - a double charge destroys coins).
+    if not _is_jailed(user):
+        return {"ok": False, "reason": "not_jailed", "balance": user["balance"]}
     if user["balance"] < MIN_BAIL:
         return {"ok": False, "reason": "broke", "balance": user["balance"]}
     pct = random.uniform(0.20, 0.30)