fix: handle cross-contract asset transfer failures with explicit checks (#104)

soroban-contracts/contracts/single_rwa_vault/src/errors.rs

@@ -56,34 +56,8 @@ pub enum Error {
     /// Burn requires pending yield to be claimed first (Option A).
     BurnRequiresYieldClaim = 32,
     InvalidDepositLimits = 33,
-    /// Timelock action not found or invalid.
-    TimelockActionNotFound = 34,
-    /// Timelock delay has not passed yet.
-    TimelockDelayNotPassed = 35,
-    /// Timelock action has already been executed.
-    TimelockActionAlreadyExecuted = 36,
-    /// Timelock action has been cancelled.
-    TimelockActionCancelled = 37,
-    /// Only admin can perform timelock operations.
-    TimelockAdminOnly = 38,
-    /// Caller is not in the emergency signers list.
-    NotEmergencySigner = 39,
-    /// The referenced emergency proposal does not exist.
-    ProposalNotFound = 40,
-    /// The emergency proposal has passed its expiry timeout.
-    ProposalExpired = 41,
-    /// The emergency proposal has already been executed.
-    ProposalAlreadyExecuted = 42,
-    /// Approval threshold has not been reached yet.
-    ThresholdNotMet = 43,
-    /// This signer has already approved this proposal.
-    AlreadyApproved = 44,
-    /// Threshold must be >= 1 and <= number of signers.
-    InvalidThreshold = 45,
-    /// Vault total assets exceeds the funding target during the funding phase.
-    FundingTargetExceeded = 46,
-    /// Amount corresponds to zero shares during preview.
-    PreviewZeroShares = 47,
-    /// Shares correspond to zero assets during preview.
-    PreviewZeroAssets = 48,
+    /// Shares are still within lock-up period and cannot be transferred
+    SharesLocked = 34,
+    /// Vault has insufficient balance to cover the requested transfer
+    InsufficientVaultBalance = 35,
 }