fix(companion): normalize heartbeat jitter random samples

src/companion/heartbeatLoop.test.ts

@@ -81,6 +81,32 @@ describe('CompanionHeartbeatLoop', () => {
     loop.stop();
   });
 
+  it('normalizes invalid randomFn samples for jitter scheduling', async () => {
+    const publishHeartbeatHigh = vi.fn(async () => buildStatusResult());
+    const loopHigh = new CompanionHeartbeatLoop(
+      { publishHeartbeat: publishHeartbeatHigh },
+      { intervalMs: 1000, jitterRatio: 0.5, randomFn: () => 2 },
+    );
+    loopHigh.start(false);
+    await vi.advanceTimersByTimeAsync(1499);
+    expect(publishHeartbeatHigh).toHaveBeenCalledTimes(0);
+    await vi.advanceTimersByTimeAsync(1);
+    expect(publishHeartbeatHigh).toHaveBeenCalledTimes(1);
+    loopHigh.stop();
+
+    const publishHeartbeatNaN = vi.fn(async () => buildStatusResult());
+    const loopNaN = new CompanionHeartbeatLoop(
+      { publishHeartbeat: publishHeartbeatNaN },
+      { intervalMs: 1000, jitterRatio: 0.5, randomFn: () => Number.NaN },
+    );
+    loopNaN.start(false);
+    await vi.advanceTimersByTimeAsync(999);
+    expect(publishHeartbeatNaN).toHaveBeenCalledTimes(0);
+    await vi.advanceTimersByTimeAsync(1);
+    expect(publishHeartbeatNaN).toHaveBeenCalledTimes(1);
+    loopNaN.stop();
+  });
+
   it('calls onSuccess with heartbeat result payload', async () => {
     const result = buildStatusResult();
     const publishHeartbeat = vi.fn(async () => result);

src/companion/heartbeatLoop.ts

@@ -154,7 +154,8 @@ export class CompanionHeartbeatLoop {
     }
     const minFactor = 1 - this.jitterRatio;
     const maxFactor = 1 + this.jitterRatio;
-    const random = this.randomFn();
+    const sampled = this.randomFn();
+    const random = Number.isFinite(sampled) ? Math.max(0, Math.min(1, sampled)) : 0.5;
     const factor = minFactor + (maxFactor - minFactor) * random;
     return Math.max(1, Math.round(this.intervalMs * factor));
   }