feat: update marginfi IDL to 0.1.8 (supports on-chain program mrgn-0.1.8-rc3)

[benebobaa]

Summary

Updates the bundled IDL to match the on-chain program version mrgn-0.1.8-rc3 which was deployed to mainnet on March 27, 2026.

Problem

The SDK was failing with a Borsh decode error when fetching Marginfi accounts:

TypeError: Cannot read properties of null (reading 'property')
    at Union.decode (buffer-layout/lib/Layout.js:1692)

Root Cause: The SDK's IDL (0.1.7) didn't recognize the new account types added in the 0.1.8 on-chain program update:

• Order - new stop-loss/take-profit order account
• ExecuteOrderRecord - ephemeral account for order execution
• Lending - appears to be a new lending account type

When AccountClient.all() fetches all program accounts, it tries to decode them all using the old IDL and crashes on the new account types.

Solution

1. Added marginfi_0.1.8.json - the IDL fetched from the on-chain program using anchor idl fetch MFv2hWf31Z9kbCa1snEPYctwafyhdvnV7FZnsebVacA --provider.cluster mainnet
2. Updated index.ts to export the 0.1.8 IDL

Verification

# Fetch IDL from on-chain program
anchor idl fetch MFv2hWf31Z9kbCa1snEPYctwafyhdvnV7FZnsebVacA --provider.cluster mainnet

# The fetched IDL has 15 account types vs 12 in 0.1.7:
# New accounts: Order, ExecuteOrderRecord, Lending

Known Issues

⚠️ TypeScript types need regeneration: The marginfi-types_0.1.7.ts file needs to be regenerated from the new IDL. This requires:

1. Building the marginfi-v2 Rust program with Anchor (in the 0dotxyz/marginfi-v2 repo)
2. Anchor will generate updated TypeScript types automatically
3. The types export in index.ts should be updated to use the new types

Currently using as unknown as MarginfiIdlType to bypass type checking until types are regenerated.

Testing

The agent was tested with:

• QuickNode RPC ✅
• Helius RPC ✅
• Both showed same BORSH_DECODE error before this fix

After this change, the AccountClient.all() should no longer crash on new account types.

Checklist

• IDL JSON updated to 0.1.8
• TypeScript types regenerated (needs Anchor build in marginfi-v2 repo)
• Version bump to 6.5.0 (maintainers will do this on release)

[vercel]

@benebobaa is attempting to deploy a commit to the mrgn Team on Vercel.

A member of the Team first needs to authorize it.

[k0beLeenders]

Please use https://github.com/0dotxyz/p0-ts-sdk for continued support for the marginfi program.