Fix large config ID precision loss in telemetry reporting (#108)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: jkebinger

src/__tests__/telemetry/evaluationSummaries.test.ts

@@ -356,4 +356,31 @@ describe("evaluationSummaries", () => {
       );
     });
   });
+
+  it("preserves large config IDs without precision loss", async () => {
+    const largeConfigId = Long.fromString("17537369033474523");
+    const largeConfig: Config = {
+      ...basicConfig,
+      id: largeConfigId,
+    };
+
+    const aggregator = evaluationSummaries(
+      mockApiClient,
+      telemetrySource,
+      instanceHash,
+      true
+    );
+
+    aggregator.push(evaluationFor(largeConfig, usContexts));
+
+    const syncResult = await aggregator.sync();
+
+    if (syncResult === undefined) {
+      throw new Error("syncResult is undefined");
+    }
+
+    const counter = syncResult.dataSent.events[0].summaries?.summaries[0].counters[0];
+    expect(counter?.configId?.toString()).toBe("17537369033474523");
+    expect(counter?.configId?.equals(largeConfigId)).toBe(true);
+  });
 });

src/telemetry/evaluationSummaries.ts

@@ -144,7 +144,7 @@ export const evaluationSummaries = (
           }
 
           const counter: ConfigEvaluationCounter = {
-            configId: Long.fromNumber(configId),
+            configId: Long.fromString(configId),
             conditionalValueIndex,
             configRowIndex,
             selectedValue,