fix(pump): default token program to legacy SPL Token instead of Token-2022

The `effective_pump_mint_token_program` helper was defaulting to
TOKEN_PROGRAM_2022 when `token_program` was Pubkey::default(), causing
Anchor error 0xbbf (account owned by wrong program) for all legacy
PumpFun coins whose ATAs are owned by the original Token Program.

Fall back to TOKEN_PROGRAM (legacy) when no explicit token program is
provided. Token-2022 must be set explicitly for create_v2 coins.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/instruction/pumpfun.rs

@@ -34,7 +34,7 @@ use solana_sdk::{instruction::Instruction, pubkey::Pubkey, signer::Signer};
 fn effective_pump_mint_token_program(protocol_params: &PumpFunParams) -> Pubkey {
     let tp = protocol_params.token_program;
     if tp == Pubkey::default() {
-        TOKEN_PROGRAM_2022
+        crate::constants::TOKEN_PROGRAM // legacy SPL Token — safe default; Token-2022 must be explicit
     } else {
         tp
     }