ci: scoped 100% coverage gates + policy doc

frontend/src/lib/backoff.test.ts

@@ -20,6 +20,23 @@ describe("createExponentialBackoff", () => {
     expect(backoff.nextDelayMs()).toBe(250); // capped
   });
 
+  it("clamps invalid numeric options and treats negative jitter as zero", () => {
+    vi.spyOn(Math, "random").mockReturnValue(0.9999);
+
+    // baseMs: NaN should clamp to min (50)
+    // maxMs: Infinity should clamp to min (= baseMs)
+    // jitter: negative -> treated as 0 (no extra delay)
+    const backoff = createExponentialBackoff({
+      baseMs: Number.NaN,
+      maxMs: Number.POSITIVE_INFINITY,
+      jitter: -1,
+    });
+
+    // With maxMs clamped to baseMs, delay will always be baseMs
+    expect(backoff.nextDelayMs()).toBe(50);
+    expect(backoff.nextDelayMs()).toBe(50);
+  });
+
   it("reset brings attempt back to zero", () => {
     vi.spyOn(Math, "random").mockReturnValue(0);
 
@@ -30,4 +47,15 @@ describe("createExponentialBackoff", () => {
     backoff.reset();
     expect(backoff.attempt()).toBe(0);
   });
+
+  it("uses defaults when options are omitted", () => {
+    vi.spyOn(Math, "random").mockReturnValue(0);
+
+    const backoff = createExponentialBackoff();
+    expect(backoff.attempt()).toBe(0);
+
+    // Default baseMs is 1000 (clamped within bounds), jitter default is 0.2.
+    // With Math.random=0, delay should be the normalized base (1000).
+    expect(backoff.nextDelayMs()).toBe(1000);
+  });
 });