fix: support Xcode 26.4 BuildOperationMetrics JSON format change

Xcode 26.4 changed the BuildOperationMetrics JSON format from
`{"clangCacheHits":0,"clangCacheMisses":2,"swiftCacheHits":0,"swiftCacheMisses":8}`
to `{"counters":{},"taskCounters":{"SwiftDriver":{...}}}`.

Make existing cache fields optional and add new `counters` and
`taskCounters` fields to support both old and new formats.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: giginet <giginet.net@gmail.com>

Author: giginet

Sources/XCLogParser/activityparser/IDEActivityModel.swift

@@ -774,21 +774,30 @@ public class IDEActivityLogSectionAttachment: Encodable {
     }
 
     public struct BuildOperationMetrics: Codable {
-        public let clangCacheHits: Int
-        public let clangCacheMisses: Int
-        public let swiftCacheHits: Int
-        public let swiftCacheMisses: Int
+        // Xcode 15.3 - Xcode 16.x format
+        public let clangCacheHits: Int?
+        public let clangCacheMisses: Int?
+        public let swiftCacheHits: Int?
+        public let swiftCacheMisses: Int?
+
+        // Xcode 26.4+ format
+        public let counters: [String: Int]?
+        public let taskCounters: [String: [String: Int]]?
 
         public init(
-            clangCacheHits: Int,
-            clangCacheMisses: Int,
-            swiftCacheHits: Int,
-            swiftCacheMisses: Int
+            clangCacheHits: Int? = nil,
+            clangCacheMisses: Int? = nil,
+            swiftCacheHits: Int? = nil,
+            swiftCacheMisses: Int? = nil,
+            counters: [String: Int]? = nil,
+            taskCounters: [String: [String: Int]]? = nil
         ) {
             self.clangCacheHits = clangCacheHits
             self.clangCacheMisses = clangCacheMisses
             self.swiftCacheHits = swiftCacheHits
             self.swiftCacheMisses = swiftCacheMisses
+            self.counters = counters
+            self.taskCounters = taskCounters
         }
     }
 }