Render ready-due queue-latency age on the Waterline dashboard Runnable tasks card

Adds an "oldest ready N waiting (since ISO)" meta line under the
existing "delayed, leased" breakdown that reads
operator_metrics.tasks.max_ready_due_age_ms and
operator_metrics.tasks.oldest_ready_due_at, mirroring the
stuck-lease-age meta already rendered on the Unhealthy tasks card.
The meta line is gated by operatorReadyDueAgeAvailable() so
dashboards backed by workflow packages that predate the ready-due
age contract continue to render without the meta.

Pins V2DashboardStatsControllerTest::testIndexExposesReadyDueAge
for the new operator_metrics.tasks keys. The assertion self-skips
when the vendored workflow package predates the contract, matching
the stuck-lease-age pattern.

Author: durable-workflow-ops

public/app.js

@@ -1,5 +1,5 @@
 {
-    "/app.js": "/app.js?id=f009cb737206d1b42e9dc424606e1a1a",
+    "/app.js": "/app.js?id=2da3db07039ecaab3c6709cc7c78e192",
     "/app-dark.css": "/app-dark.css?id=14bdc4fb1d6331a94030dc13821344fb",
     "/app.css": "/app.css?id=3d56d0e6a90f99083d111a8474a3c271",
     "/img/favicon.png": "/img/favicon.png?id=7c006241b093796d6abfa3049df93a59",

public/mix-manifest.json

@@ -297,6 +297,12 @@
                                     {{ operatorMetricLabel('backlog', 'delayed_tasks') }} delayed,
                                     {{ operatorMetricLabel('backlog', 'leased_tasks') }} leased
                                 </div>
+                                <div v-if="operatorReadyDueAgeAvailable()" class="wl-operator-metric__meta">
+                                    oldest ready {{ operatorDurationMetricLabel('tasks', 'max_ready_due_age_ms') }} waiting
+                                    <template v-if="operatorReadyDueOldestAt()">
+                                        (since {{ operatorReadyDueOldestAt() }})
+                                    </template>
+                                </div>
                             </div>
                             <div class="wl-operator-metric">
                                 <div class="wl-operator-metric__label">Unhealthy tasks</div>
@@ -1140,6 +1146,24 @@ export default {
             return tasks.oldest_lease_expired_at || null;
         },
 
+        operatorReadyDueAgeAvailable() {
+            const tasks = (this.operatorMetrics && this.operatorMetrics.tasks) || {};
+
+            if (tasks.max_ready_due_age_ms === undefined
+                || tasks.max_ready_due_age_ms === null) {
+                return false;
+            }
+
+            return Number(tasks.ready_due || 0) > 0
+                || Number(tasks.max_ready_due_age_ms || 0) > 0;
+        },
+
+        operatorReadyDueOldestAt() {
+            const tasks = (this.operatorMetrics && this.operatorMetrics.tasks) || {};
+
+            return tasks.oldest_ready_due_at || null;
+        },
+
         operatorSchedulesAvailable() {
             const schedules = this.operatorMetrics && this.operatorMetrics.schedules;
 

resources/js/screens/dashboard.vue

@@ -762,4 +762,34 @@ public function testIndexExposesStuckLeaseAge(): void
             'operator_metrics.tasks.max_lease_expired_age_ms must be null or integer milliseconds',
         );
     }
+
+    public function testIndexExposesReadyDueAge(): void
+    {
+        config()->set('waterline.engine_source', 'v2');
+
+        $response = $this->get('/waterline/api/stats')->assertStatus(200);
+
+        $tasks = $response->json('operator_metrics.tasks');
+
+        $this->assertIsArray($tasks);
+
+        if (! array_key_exists('max_ready_due_age_ms', $tasks)
+            || ! array_key_exists('oldest_ready_due_at', $tasks)) {
+            $this->markTestSkipped(
+                'Vendored workflow package predates the ready-due age rollout-safety contract '
+                . '(operator_metrics.tasks.oldest_ready_due_at / max_ready_due_age_ms).',
+            );
+        }
+
+        $this->assertTrue(
+            $tasks['oldest_ready_due_at'] === null
+                || is_string($tasks['oldest_ready_due_at']),
+            'operator_metrics.tasks.oldest_ready_due_at must be null or ISO-8601 string',
+        );
+        $this->assertTrue(
+            $tasks['max_ready_due_age_ms'] === null
+                || is_int($tasks['max_ready_due_age_ms']),
+            'operator_metrics.tasks.max_ready_due_age_ms must be null or integer milliseconds',
+        );
+    }
 }