feat(economy): add vanity shop and harden economy money-safety

Vanity shop (/vanity): cosmetic badges/titles as a pure whale coin sink -
purchases burn coins (not credited to the house) and equip a badge shown on
/profile. New vanity_owned/vanity_active fields, schema sync, and tests.

Money-safety and robustness fixes from a codebase review:

- _parse_amount now rejects negative amounts. Every bet/give/request flows
  through it, so a negative value can no longer mint coins on a loss/transfer
  path that trusts the caller's sign (all call sites already guarded <= 0;
  this closes the source).
- do_blackjack_payout no longer raises on a DB failure. The stake was already
  deducted in do_blackjack_bet, so it now logs critical with the owed amount
  (for admin reconciliation) and returns db_error; all payout call sites render
  a clear "payout failed" notice instead of crashing the interaction.
- Instant "kohv" consumable now cancels the pending reminder DMs for the
  cooldowns it wipes (via new INSTANT_RESET_COMMANDS), so no stale/duplicate
  reminders fire.
- Renamed the misleadingly-named _refund_user_safe -> _debit_house_safe (it
  debits the house) and dropped its ignored first arg.
- Added __all__ to vanity.py and consumables.py so `import *` no longer leaks
  incidental imports into the economy namespace.
- Documented Kõrvaklapid's +25 coin daily bonus in README and DEV_NOTES.

Tests: blackjack payout DB-failure safety and INSTANT_RESET_COMMANDS lockstep.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013VbAVsrZuYesea99mPMmPT

core/economy/house.py

@@ -75,9 +75,10 @@ async def _refund_house_safe(amount: int, context: str, related_uid: int) -> Non
         )
 
 
-async def _refund_user_safe(_unused_house_id, amount: int, context: str, uid: int) -> None:
-    """Best-effort atomic debit of `amount` from the house (compensates a failed
-    user fine). Logs critical if it fails."""
+async def _debit_house_safe(amount: int, context: str, uid: int) -> None:
+    """Best-effort atomic debit of `amount` from the house. Compensates a fine
+    that was credited to the house but whose matching user debit failed to persist
+    (the coins must be pulled back out of the house). Logs critical if it fails."""
     if HOUSE_ID is None or amount <= 0:
         return
     try: