feat(trading): zero-RPC extreme-fast buys and listener race hardening (#170) (#183)

Extreme-fast mode submits with no RPC calls between detection and buy
when the listener parsed the on-chain CreateEvent (geyser/logs/blocks):
TokenInfo.state_from_event carries the canonical creator, mayhem/cashback
flags and quote_mint, so the pre-buy curve refresh is skipped. The geyser
listener now delegates to the event-first parser instead of inlining
instruction decoding, which also catches create_v2 transactions that omit
the trailing is_cashback_enabled byte.

Listeners without event data (pumpportal) keep the refresh, hardened per
issue #170: bonding curve derived from the mint instead of the payload's
bondingCurveKey, curve and mint read in one slot-consistent
getMultipleAccounts (correcting the guessed token program), and an
unreadable curve now skips the token within trade.curve_refresh_budget
instead of submitting a buy built from guessed accounts.

Machine-checked by verify_extreme_fast_zero_rpc.py and
verify_pumpportal_buy_path.py; validated live via simulate_bot_buy_path
on both geyser and pumpportal paths.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

learning-examples/verify_tx_status_checks.py

@@ -144,6 +144,9 @@ async def check_examples_call_a_status_check() -> None:
         Path(__file__).name,
         # stubs confirm_transaction out; never sends a transaction
         "simulate_bot_buy_path.py",
+        # offline checks with a stub client; never sends a transaction
+        "verify_pumpportal_buy_path.py",
+        "verify_extreme_fast_zero_rpc.py",
         # uses the bot's SolanaClient wrapper, which folds meta.err into its
         # return value; the boolean is read at the call site
         "cleanup_accounts.py",