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>

strings.py

@@ -1167,6 +1167,7 @@ JAILBREAK_UI: dict[str, str] = {
     "bail_btn":         "💸 Maksa kautsjon",
     "bail_broke_desc":  "❌ Sul pole piisavalt raha (min {min}).\nJääd vanglasse kuni aja lõpuni! Saldo: {balance}",
     "bail_paid_desc":   "✅ Kautsjon makstud: **{fine}**\nOled vaba! Saldo: {balance}",
+    "bail_already_free": "✅ Oled juba vaba - kautsjonit ei võetud. Saldo: {balance}",
     "fail_broke_desc":  "{d1}  {d2} - ei olnud duubel\n\n❌ Sul pole kautsjoni maksmiseks piisavalt raha (min 350 ⬡).\nJääd vanglasse kuni aja lõpuni! Saldo: {balance}",
     "fail_bail_desc":   "{d1}  {d2} - ei olnud duubel\n\nKautsjon makstud: **{fine}**\nSaldo: {balance}",
     "fail_bail_offer":  "{d1}  {d2} - ei olnud duubel\n\n💰 **Kautsjon: {min} - {max}** (20-30% saldost)\nSaldo: {bal}\n\nSaad maksta kautsjoni või jääda vanglasse kuni aja lõpuni.",