feat(usage): include cache tokens in total token calculation and add tests

- Updated `TotalTokens` calculation to account for `CacheReadTokens` and `CacheCreationTokens`.
- Added tests to validate accurate token aggregation and fallback behavior for `CachedTokens`.

Author: luispater

internal/runtime/executor/helps/usage_helpers.go

@@ -527,7 +527,7 @@ func parseClaudeUsageNode(usageNode gjson.Result) usage.Detail {
 	if detail.CachedTokens == 0 {
 		detail.CachedTokens = detail.CacheCreationTokens
 	}
-	detail.TotalTokens = detail.InputTokens + detail.OutputTokens
+	detail.TotalTokens = detail.InputTokens + detail.OutputTokens + detail.CacheReadTokens + detail.CacheCreationTokens
 	return detail
 }
 

internal/runtime/executor/helps/usage_helpers_test.go

@@ -89,6 +89,40 @@ func TestParseOpenAIStreamUsageResponsesFields(t *testing.T) {
 	}
 }
 
+func TestParseClaudeUsageIncludesCacheTokensInTotal(t *testing.T) {
+	data := []byte(`{"usage":{"input_tokens":3085,"output_tokens":253,"cache_read_input_tokens":7,"cache_creation_input_tokens":19514}}`)
+	detail := ParseClaudeUsage(data)
+	if detail.InputTokens != 3085 {
+		t.Fatalf("input tokens = %d, want %d", detail.InputTokens, 3085)
+	}
+	if detail.OutputTokens != 253 {
+		t.Fatalf("output tokens = %d, want %d", detail.OutputTokens, 253)
+	}
+	if detail.CacheReadTokens != 7 {
+		t.Fatalf("cache read tokens = %d, want %d", detail.CacheReadTokens, 7)
+	}
+	if detail.CacheCreationTokens != 19514 {
+		t.Fatalf("cache creation tokens = %d, want %d", detail.CacheCreationTokens, 19514)
+	}
+	if detail.CachedTokens != 7 {
+		t.Fatalf("cached tokens = %d, want %d", detail.CachedTokens, 7)
+	}
+	if detail.TotalTokens != 22859 {
+		t.Fatalf("total tokens = %d, want %d", detail.TotalTokens, 22859)
+	}
+}
+
+func TestParseClaudeUsageFallsBackCachedTokensToCacheCreation(t *testing.T) {
+	data := []byte(`{"usage":{"input_tokens":3085,"output_tokens":253,"cache_creation_input_tokens":19514}}`)
+	detail := ParseClaudeUsage(data)
+	if detail.CachedTokens != 19514 {
+		t.Fatalf("cached tokens = %d, want %d", detail.CachedTokens, 19514)
+	}
+	if detail.TotalTokens != 22852 {
+		t.Fatalf("total tokens = %d, want %d", detail.TotalTokens, 22852)
+	}
+}
+
 func TestParseGeminiCLIUsage_TopLevelUsageMetadata(t *testing.T) {
 	data := []byte(`{"usageMetadata":{"promptTokenCount":11,"candidatesTokenCount":7,"thoughtsTokenCount":3,"totalTokenCount":21,"cachedContentTokenCount":5}}`)
 	detail := ParseGeminiCLIUsage(data)