fix(mobile): record xprem_js_crash only for fatal JS errors

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/mobile/src/__tests__/lib/observe.test.ts

@@ -75,12 +75,26 @@ describe('observe', () => {
             expect.objectContaining({
                 severity: 'fatal',
                 body: 'boom',
-                attributes: { isFatal: true },
             })
         );
         expect(previousHandler).toHaveBeenCalledWith(error, true);
     });
 
+    it('does not log xprem_js_crash for non-fatal errors but still delegates', () => {
+        const previousHandler = jest.fn();
+        const getInstalledHandler = installFakeErrorUtils(previousHandler);
+
+        withFreshObserveModule(({ installObserveGlobalErrorHandler }) => {
+            installObserveGlobalErrorHandler();
+        });
+
+        const error = new Error('handled');
+        getInstalledHandler()(error, false);
+
+        expect(logEventMock).not.toHaveBeenCalled();
+        expect(previousHandler).toHaveBeenCalledWith(error, false);
+    });
+
     it('still calls the previous handler when Observe.logEvent throws', () => {
         const previousHandler = jest.fn();
         const getInstalledHandler = installFakeErrorUtils(previousHandler);
@@ -92,8 +106,8 @@ describe('observe', () => {
             installObserveGlobalErrorHandler();
         });
 
-        getInstalledHandler()(new Error('boom'), false);
+        getInstalledHandler()(new Error('boom'), true);
 
-        expect(previousHandler).toHaveBeenCalledWith(expect.any(Error), false);
+        expect(previousHandler).toHaveBeenCalledWith(expect.any(Error), true);
     });
 });

apps/mobile/src/lib/observe.ts

@@ -50,16 +50,19 @@ export function installObserveGlobalErrorHandler() {
   const previousHandler = errorUtils.getGlobalHandler();
 
   errorUtils.setGlobalHandler((error, isFatal) => {
+    // Only fatal errors count as a crash; non-fatal handled errors would
+    // otherwise skew update-health tracking.
+    if (isFatal) {
       try {
         const message = error instanceof Error ? error.message : String(error);
         Observe.logEvent("xprem_js_crash", {
           severity: "fatal",
           body: message,
-        attributes: { isFatal: Boolean(isFatal) },
         });
       } catch (observeError) {
         console.warn("[Observe] Failed to log xprem_js_crash:", observeError);
       }
+    }
 
     previousHandler(error, isFatal);
   });