feat: governance parameter registry

Cargo.toml

@@ -6,6 +6,7 @@ members = [
 
 [workspace.dependencies]
 soroban-sdk = "25.0.0"
+ethnum = "=1.4.0"
 
 [profile.release]
 opt-level = "z"

contracts/predictify-hybrid/Cargo.toml

@@ -11,6 +11,7 @@ doctest = false
 [dependencies]
 soroban-sdk = { workspace = true }
 wee_alloc = "0.4.5"
+ethnum = "=1.4.0"
 
 
 # Disabled: pre-existing SDK incompatibilities

contracts/predictify-hybrid/src/err.rs

@@ -245,6 +245,22 @@ pub enum Error {
     ReplayedOverride = 526,
     /// Oracle quote is an outlier relative to the rolling median history.
     OracleQuoteOutlier = 527,
+
+    // ===== GOVERNANCE REGISTRY ERRORS (600-609) =====
+    /// Governance registry has already been initialized.
+    AlreadyInitialized = 600,
+    /// Registry not yet initialized. Call initialize() first.
+    RegistryNotInitialized = 601,
+    /// Parameter key is empty or invalid.
+    InvalidKey = 602,
+    /// A pending update already exists for this parameter.
+    PendingUpdateExists = 603,
+    /// No pending update exists for this parameter.
+    NoPendingUpdate = 604,
+    /// Time-lock delay has not yet expired for this update.
+    TimeLockNotExpired = 605,
+    /// Time-lock delay value is invalid (must be > 0).
+    InvalidTimeLockDelay = 606,
 }
 
 // ===== ERROR CATEGORIZATION AND RECOVERY SYSTEM =====