fix(solana/docs): update ADR for universal error ack (#1011)

Co-authored-by: srdtrk <59252793+srdtrk@users.noreply.github.com>

Author: vaporif

docs/adr/solana-ics27-gmp-architecture.md

@@ -546,6 +546,7 @@ See [Per-Sender Sequence Counter](solana-storage-architecture.md#per-sender-sequ
 - **CPI Depth**: 2 levels for target programs (vs unlimited on Ethereum)
 - **Account Pre-declaration**: All accounts must be known upfront
 - **Transaction Size**: 1232-byte limit constrains complexity
+- **No error ack on CPI failure**: If the target app reverts, the whole tx rolls back - no error ack, packet stuck until timeout. See [IFT ADR](./solana-ift-architecture.md#limitations).
 
 ### Mitigation Strategies
 

docs/adr/solana-ift-architecture.md

@@ -273,6 +273,7 @@ This PDA-based validation is more efficient and Solana-native than instruction s
 
 1. **Mint Authority Transfer**: For existing tokens, authority must be transferred to IFT PDA (recoverable via `revoke_mint_authority`)
 2. **No WSOL**: Native SOL bridging requires ICS-20
+3. **No error ack on CPI failure**: On Ethereum the router can catch an app revert and still write an error ack. Solana doesn't work that way - a failed CPI takes down the whole transaction, so the router never gets a chance to write anything. The `Err` branch in `recv_packet.rs` is `unreachable!()`. If `ift_mint` or any callback keeps reverting, the packet just sits there until timeout. Relayers should cap retries and simulate first.
 
 ## References
 

programs/solana/programs/ics26-router/src/instructions/recv_packet.rs

@@ -14,6 +14,12 @@ use solana_ibc_types::ics24;
 ///
 /// Remaining accounts carry payload chunks, proof chunks and any extra
 /// accounts forwarded to the IBC app.
+///
+/// # CPI failure = entire tx reverts
+///
+/// Solana has no try/catch for CPI. If the app reverts, the whole transaction
+/// rolls back and the packet stays unacknowledged (timeout is the only recovery).
+/// See `docs/adr/solana-ift-architecture.md` limitations section.
 #[derive(Accounts)]
 #[instruction(msg: MsgRecvPacket)]
 pub struct RecvPacket<'info> {