fix(cron): use effectiveStatus for recurring job backoff scheduling

Missed substitution on line 420: the recurring-job backoff branch still
checked result.status instead of effectiveStatus, so a job that delivered
successfully (delivered=true) could still have its nextRunAtMs pushed out
by error backoff even though all status fields showed ok.

Also adds a nextRunAtMs assertion for the delivered=true override case.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/cron/service/timer.apply-job-result.test.ts

@@ -137,4 +137,31 @@ describe("applyJobResult – delivered=true overrides error status (#50170)", ()
     expect(job.state.lastRunStatus).toBe("ok");
     expect(job.state.consecutiveErrors).toBe(0);
   });
+
+  it("does not apply error backoff to nextRunAtMs for recurring job when delivered=true overrides error", () => {
+    // Use a high-frequency schedule so the backoff (30 s minimum) would
+    // exceed the natural interval and push nextRunAtMs out if applied.
+    const schedule = { kind: "every" as const, intervalMs: 5_000 };
+
+    const jobError = createJob({ schedule });
+    const jobOk = createJob({ id: "test-job-2", schedule });
+    const stateError = createMockState([jobError]);
+    const stateOk = createMockState([jobOk]);
+
+    applyJobResult(stateError, jobError, {
+      ...BASE_RESULT,
+      status: "error",
+      error: "Warning: Canvas failed",
+      delivered: true,
+    });
+
+    applyJobResult(stateOk, jobOk, {
+      ...BASE_RESULT,
+      status: "ok",
+      delivered: true,
+    });
+
+    // Both should schedule the same natural next run — no backoff on delivered=true.
+    expect(jobError.state.nextRunAtMs).toBe(jobOk.state.nextRunAtMs);
+  });
 });

src/cron/service/timer.ts

@@ -417,7 +417,7 @@ export function applyJobResult(
           );
         }
       }
-    } else if (result.status === "error" && job.enabled) {
+    } else if (effectiveStatus === "error" && job.enabled) {
       // Apply exponential backoff for errored jobs to prevent retry storms.
       const backoff = errorBackoffMs(job.state.consecutiveErrors ?? 1);
       let normalNext: number | undefined;