Update dependencies and fix hex string initialization

- Update BigInt to 5.7.0
- Pin secp256k1.swift to exact version 0.12.2
- Update Swift package dependencies (NIO, collections, HTTP types, etc.)
- Add new Swift package dependencies (swift-asn1, swift-async-algorithms, swift-certificates, swift-crypto, swift-service-lifecycle)
- Fix empty hex string handling in HexExtensions to initialize to 0 instead of nil

Author: dioKaratzas

Package.resolved

@@ -15,7 +15,7 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/attaswift/BigInt", from: "5.3.0"),
         .package(url: "https://github.com/iwill/generic-json-swift", .upToNextMajor(from: "2.0.2")),
-        .package(url: "https://github.com/GigaBitcoin/secp256k1.swift.git", .upToNextMajor(from: "0.6.0")),
+        .package(url: "https://github.com/GigaBitcoin/secp256k1.swift.git", exact: "0.12.2"),
         .package(url: "https://github.com/vapor/websocket-kit.git", from: "2.16.1"),
         .package(url: "https://github.com/apple/swift-log.git", from: "1.6.4")
     ],

Package.swift

@@ -15,7 +15,7 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/attaswift/BigInt", from: "5.3.0"),
         .package(url: "https://github.com/iwill/generic-json-swift", .upToNextMajor(from: "2.0.2")),
-        .package(url: "https://github.com/GigaBitcoin/secp256k1.swift.git", .upToNextMajor(from: "0.6.0")),
+        .package(url: "https://github.com/GigaBitcoin/secp256k1.swift.git", exact: "0.12.2"),
         .package(url: "https://github.com/vapor/websocket-kit.git", from: "2.16.1"),
         .package(url: "https://github.com/apple/swift-log.git", from: "1.6.4")
     ],

Package@swift-6.1.swift

@@ -8,7 +8,12 @@ import Foundation
 
 public extension BigUInt {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix.lowercased(), radix: 16)
+        let stripped = hex.web3.noHexPrefix.lowercased()
+        if stripped.isEmpty {
+            self.init(0)
+        } else {
+            self.init(stripped, radix: 16)
+        }
     }
 }
 
@@ -24,13 +29,23 @@ public extension Web3Extensions where Base == BigUInt {
 
 public extension BigInt {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix.lowercased(), radix: 16)
+        let stripped = hex.web3.noHexPrefix.lowercased()
+        if stripped.isEmpty {
+            self.init(0)
+        } else {
+            self.init(stripped, radix: 16)
+        }
     }
 }
 
 public extension Int {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix, radix: 16)
+        let stripped = hex.web3.noHexPrefix
+        if stripped.isEmpty {
+            self.init(0)
+        } else {
+            self.init(stripped, radix: 16)
+        }
     }
 }