Remove the fund-seat instruction from the Solana SDK (malbeclabs/doublezero-offchain#416)

Closes malbeclabs/infra#2410.

## Summary
- The Solana SDK no longer builds a fund-seat instruction.
- `doublezero-solana shreds payments` still reads leftover fund
transactions so escrow history stays intact.
- Close and withdraw stay so a holder can pull unused USDC.

Author: martinsander00

offchain/crates/solana-cli/CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- `shreds payments`: keep reading leftover fund-seat transactions after the SDK drops that instruction (malbeclabs/infra#2411)
 - `shreds pay`: remove the command. `shreds withdraw`, `list`, `payments`, and `price` stay (malbeclabs/infra#2410)
 - `shreds`: collapse `pay`'s `SLOT_DURATION_SECS` and `prepare-offchain-message`'s `SLOT_DURATION_MS` into one `NOMINAL_SLOT_DURATION` at 350ms, matching mainnet-beta from epoch 1020 (2026-08-21). Deliberately cluster-independent, because a `~` prefixed estimate and a deadline slot the CLI and operator must both compute want reproducibility over accuracy. `--valid-for 1h` now resolves to 10,285 slots rather than 9,000, and the epoch-remaining estimates shrink by an eighth. Testnet runs at 200ms, so its estimates stay wrong in the other direction, and SIMD-0525 will need one more bump here (malbeclabs/infra#2317)
 - `shreds validator-client-rewards`: read the `ValidatorClientRewards` account through the SDK's zero-copy mirror instead of the hand-written byte-offset parser. Every subcommand now requires at least 184 bytes of account data rather than 116

offchain/crates/solana-cli/src/command/shreds/payments.rs

@@ -83,6 +83,15 @@ impl std::fmt::Display for EventType {
     }
 }
 
+const LEGACY_FUND_PAYMENT_ESCROW_USDC: [u8; 8] = [111, 6, 96, 2, 121, 92, 68, 147];
+
+fn parse_legacy_fund_payment_escrow_usdc(data: &[u8]) -> Option<u64> {
+    if data.len() < 16 || data[..8] != LEGACY_FUND_PAYMENT_ESCROW_USDC {
+        return None;
+    }
+    Some(u64::from_le_bytes(data[8..16].try_into().ok()?))
+}
+
 impl PaymentsCommand {
     pub async fn execute(
         self,
@@ -194,14 +203,16 @@ impl PaymentsCommand {
                         continue;
                     }
 
+                    if let Some(amount) = parse_legacy_fund_payment_escrow_usdc(&ix.data) {
+                        events.push(PaymentEvent {
+                            event_type: EventType::Funded,
+                            amount_micro: amount as i64,
+                            block_time: tx_response.block_time,
+                        });
+                        continue;
+                    }
+
                     match ShredSubscriptionInstructionData::try_from_slice(&ix.data) {
-                        Ok(ShredSubscriptionInstructionData::FundPaymentEscrowUsdc(amount)) => {
-                            events.push(PaymentEvent {
-                                event_type: EventType::Funded,
-                                amount_micro: amount as i64,
-                                block_time: tx_response.block_time,
-                            });
-                        }
                         // TODO: ClosePaymentEscrow (withdrawal) — the actual
                         // refunded amount is in the tx log message "Withdrew {}
                         // USDC from payment escrow to refund account". Parse that

offchain/crates/solana-sdk/src/shred_subscription/instruction/account.rs

@@ -366,71 +366,6 @@ impl From<CheckCliVersionAccounts> for Vec<AccountMeta> {
     }
 }
 
-/// Accounts for the `FundPaymentEscrowUsdc` instruction (10 accounts).
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct FundPaymentEscrowUsdcAccounts {
-    pub program_config_key: Pubkey,
-    pub execution_controller_key: Pubkey,
-    pub metro_history_key: Pubkey,
-    pub device_history_key: Pubkey,
-    pub client_seat_key: Pubkey,
-    pub payment_escrow_key: Pubkey,
-    pub device_history_usdc_token_account_key: Pubkey,
-    pub source_usdc_token_account_key: Pubkey,
-    pub transfer_authority_key: Pubkey,
-}
-
-impl FundPaymentEscrowUsdcAccounts {
-    pub fn new(
-        exchange_key: &Pubkey,
-        device_key: &Pubkey,
-        client_ip_bits: u32,
-        withdraw_authority_key: &Pubkey,
-        usdc_mint_key: &Pubkey,
-        source_usdc_token_account_key: &Pubkey,
-        transfer_authority_key: &Pubkey,
-    ) -> Self {
-        let client_seat_key = state::find_client_seat_address(device_key, client_ip_bits).0;
-        let device_history_key = state::find_device_history_address(device_key).0;
-        Self {
-            program_config_key: state::find_program_config_address().0,
-            execution_controller_key: state::find_execution_controller_address().0,
-            metro_history_key: state::find_metro_history_address(exchange_key).0,
-            device_history_key,
-            client_seat_key,
-            payment_escrow_key: state::find_payment_escrow_address(
-                &client_seat_key,
-                withdraw_authority_key,
-            )
-            .0,
-            device_history_usdc_token_account_key: state::find_token_pda_address(
-                &device_history_key,
-                usdc_mint_key,
-            )
-            .0,
-            source_usdc_token_account_key: *source_usdc_token_account_key,
-            transfer_authority_key: *transfer_authority_key,
-        }
-    }
-}
-
-impl From<FundPaymentEscrowUsdcAccounts> for Vec<AccountMeta> {
-    fn from(accounts: FundPaymentEscrowUsdcAccounts) -> Self {
-        vec![
-            AccountMeta::new_readonly(accounts.program_config_key, false),
-            AccountMeta::new(accounts.execution_controller_key, false),
-            AccountMeta::new_readonly(accounts.metro_history_key, false),
-            AccountMeta::new_readonly(accounts.device_history_key, false),
-            AccountMeta::new(accounts.client_seat_key, false),
-            AccountMeta::new(accounts.payment_escrow_key, false),
-            AccountMeta::new(accounts.device_history_usdc_token_account_key, false),
-            AccountMeta::new(accounts.source_usdc_token_account_key, false),
-            AccountMeta::new_readonly(accounts.transfer_authority_key, true),
-            AccountMeta::new_readonly(spl_token_interface::ID, false),
-        ]
-    }
-}
-
 /// Accounts for the `InitializeClaimHolding` instruction (6 accounts).
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InitializeClaimHoldingAccounts {

offchain/crates/solana-sdk/src/shred_subscription/instruction/mod.rs

@@ -34,8 +34,6 @@ pub enum ShredSubscriptionInstructionData {
     InitializePaymentEscrow,
     /// Close a payment escrow and refund any remaining USDC.
     ClosePaymentEscrow,
-    /// Fund a payment escrow with USDC.
-    FundPaymentEscrowUsdc(u64),
     /// Request instant allocation for a funded seat (skips auction settlement).
     RequestInstantSeatAllocation,
     /// Request instant seat withdrawal.
@@ -88,8 +86,6 @@ impl ShredSubscriptionInstructionData {
         Discriminator::new_sha2(b"dz::ix::initialize_payment_escrow");
     pub const CLOSE_PAYMENT_ESCROW: Discriminator<DISCRIMINATOR_LEN> =
         Discriminator::new_sha2(b"dz::ix::close_payment_escrow");
-    pub const FUND_PAYMENT_ESCROW_USDC: Discriminator<DISCRIMINATOR_LEN> =
-        Discriminator::new_sha2(b"dz::ix::fund_payment_escrow_usdc");
     pub const REQUEST_INSTANT_SEAT_ALLOCATION: Discriminator<DISCRIMINATOR_LEN> =
         Discriminator::new_sha2(b"dz::ix::request_instant_seat_allocation");
     pub const REQUEST_INSTANT_SEAT_WITHDRAWAL: Discriminator<DISCRIMINATOR_LEN> =
@@ -121,10 +117,6 @@ impl BorshSerialize for ShredSubscriptionInstructionData {
             }
             Self::InitializePaymentEscrow => Self::INITIALIZE_PAYMENT_ESCROW.serialize(writer),
             Self::ClosePaymentEscrow => Self::CLOSE_PAYMENT_ESCROW.serialize(writer),
-            Self::FundPaymentEscrowUsdc(amount) => {
-                Self::FUND_PAYMENT_ESCROW_USDC.serialize(writer)?;
-                amount.serialize(writer)
-            }
             Self::RequestInstantSeatAllocation => {
                 Self::REQUEST_INSTANT_SEAT_ALLOCATION.serialize(writer)
             }
@@ -189,10 +181,6 @@ impl BorshDeserialize for ShredSubscriptionInstructionData {
             }
             Self::INITIALIZE_PAYMENT_ESCROW => Ok(Self::InitializePaymentEscrow),
             Self::CLOSE_PAYMENT_ESCROW => Ok(Self::ClosePaymentEscrow),
-            Self::FUND_PAYMENT_ESCROW_USDC => {
-                let amount = u64::deserialize_reader(reader)?;
-                Ok(Self::FundPaymentEscrowUsdc(amount))
-            }
             Self::REQUEST_INSTANT_SEAT_ALLOCATION => Ok(Self::RequestInstantSeatAllocation),
             Self::REQUEST_INSTANT_SEAT_WITHDRAWAL => Ok(Self::RequestInstantSeatWithdrawal),
             Self::REQUEST_PRORATED_INSTANT_SEAT_WITHDRAWAL => {