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>

commands/economy_extra_commands.py

@@ -396,12 +396,17 @@ def register_economy_extra_commands(
         def __init__(self, user_id: int):
             super().__init__(timeout=60)
             self.user_id = user_id
+            self._paying = False
 
         @discord.ui.button(label=S.JAILBREAK_UI["bail_btn"], style=discord.ButtonStyle.danger)
         async def pay_bail(self, interaction: discord.Interaction, _: discord.ui.Button):
             if interaction.user.id != self.user_id:
                 await interaction.response.send_message(S.ERR["not_your_game"], ephemeral=True)
                 return
+            if self._paying or self.is_finished():
+                await interaction.response.defer()
+                return
+            self._paying = True
             res = await economy.do_bail(self.user_id)
             self.clear_items()
             self.stop()
@@ -414,6 +419,15 @@ def register_economy_extra_commands(
                     ),
                     color=0xED4245,
                 )
+            elif not res["ok"]:
+                # Already released (stale view or double-click) - no charge applied.
+                embed = discord.Embed(
+                    title=S.TITLE["jailbreak_bail"],
+                    description=S.JAILBREAK_UI["bail_already_free"].format(
+                        balance=coin(res["balance"]),
+                    ),
+                    color=0x57F287,
+                )
             else:
                 embed = discord.Embed(
                     title=S.TITLE["jailbreak_bail"],