fix(examples): align listeners and decoders with refreshed pump.fun IDL

Refreshes the read-only learning examples (Phase A3) against the post
Feb–Apr 2026 IDL changes:
  - CreateEvent now has 15 fields (timestamp, 4×u64 reserves, token_program,
    is_mayhem_mode, is_cashback_enabled). Listener parsers were truncating
    after `creator`; the v2 ones were also reading is_mayhem_mode at the
    wrong offset.
  - BondingCurve account is now 83 bytes (added is_cashback_coin).
  - PumpSwap Pool account is now 245 bytes (added is_cashback_coin) — the
    listen_programsubscribe dataSize filter was matching nothing.
  - IDL instruction `createV2` was renamed to `create_v2`; the legacy
    `create` instruction added a `creator: pubkey` arg in March 2026.
  - decode_from_blockSubscribe.py decoder now handles bool, i64, u32, u16,
    u8, and the OptionBool defined type (1-byte wire format).

Files touched (all under learning-examples/):
  bonding-curve-progress/get_bonding_curve_status.py  — V4 struct (cashback)
  bonding-curve-progress/poll_bonding_curve_progress.py
  decode_from_blockSubscribe.py
  decode_from_getAccountInfo.py
  decode_from_getTransaction.py
  listen-migrations/compare_migration_listeners.py
  listen-migrations/listen_programsubscribe.py
  listen-new-tokens/compare_listeners.py
  listen-new-tokens/listen_blocksubscribe.py
  listen-new-tokens/listen_geyser.py
  listen-new-tokens/listen_logsubscribe.py
  listen-new-tokens/listen_logsubscribe_abc.py

Verified live against mainnet — listeners decode tokens including
mayhem-mode and cashback-enabled curves correctly.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

learning-examples/bonding-curve-progress/poll_bonding_curve_progress.py

@@ -104,6 +104,12 @@ def parse_curve_state(data: bytes) -> dict:
     else:
         result["is_mayhem_mode"] = False
 
+    # Parse is_cashback_coin if present (added in late-Feb 2026 cashback upgrade)
+    if data_length >= 75:
+        result["is_cashback_coin"] = bool(data[82])
+    else:
+        result["is_cashback_coin"] = False
+
     return result