refactor(sdk): rewrite NonceCache with LRU eviction, drift detection, and structured errors

packages/rs-sdk/Cargo.toml

@@ -36,7 +36,7 @@ dotenvy = { version = "0.15.7", optional = true }
 envy = { version = "0.4.2", optional = true }
 futures = { version = "0.3.30" }
 derive_more = { version = "1.0", features = ["from"] }
-lru = { version = "0.16.3", optional = true }
+lru = { version = "0.16.3" }
 bip37-bloom-filter = { git = "https://github.com/dashpay/rs-bip37-bloom-filter", branch = "develop" }
 zeroize = { version = "1.8", features = ["derive"] }
 
@@ -92,7 +92,7 @@ mocks = [
   "drive-proof-verifier/mocks",
   "dep:dotenvy",
   "dep:envy",
-  "dep:lru",
+
   "zeroize/serde",
 ]
 

packages/rs-sdk/src/error.rs

@@ -75,6 +75,22 @@ pub enum Error {
     /// Invalid credit transfer configuration
     #[error("Invalid credit transfer: {0}")]
     InvalidCreditTransfer(String),
+    /// Identity nonce overflow: the nonce has reached its maximum value and
+    /// cannot be incremented further without wrapping to zero.
+    #[error("Identity nonce overflow: nonce has reached the maximum value ({0})")]
+    NonceOverflow(u64),
+    /// Identity nonce not found on Platform.
+    ///
+    /// Platform returned no nonce for the requested identity (or identity–
+    /// contract pair).  This usually means the queried DAPI node has not yet
+    /// indexed the identity — for example right after identity creation or
+    /// when the node is lagging behind the chain tip.
+    ///
+    /// **Recovery**: retry the state transition; the SDK will re-fetch the
+    /// nonce from a (potentially different) DAPI node on the next attempt.
+    #[error("Identity nonce not found on platform: {0}")]
+    IdentityNonceNotFound(String),
+
     /// Generic error
     // TODO: Use domain specific errors instead of generic ones
     #[error("SDK error: {0}")]