fix: close durable queue and runtime gaps

packages/queue/src/durable.ts

@@ -14,7 +14,8 @@ export interface QueueStore {
   remove(id: string): Promise<void>;
   due(now: number, limit: number): Promise<Job[]>;
   list(name?: string): Promise<Job[]>;
-  findByIdempotencyKey?(name: string, key: string): Promise<Job | null>;
+  /** Indexed lookup; implementations must not scan the queue. */
+  findByIdempotencyKey(name: string, key: string): Promise<Job | null>;
   size?(): Promise<number>;
   claim?(id: string, worker: string, leaseUntil: number, now?: number): Promise<boolean>;
   release?(id: string, worker: string): Promise<void>;
@@ -175,7 +176,8 @@ export function createDurableQueue(options: DurableQueueOptions = {}): DurableQu
   const workerId = options.workerId?.trim() || `worker-${crypto.randomUUID()}`;
   const defaultMaxAttempts = positiveInteger(options.maxAttempts ?? 3, "queue maxAttempts");
   const concurrency = positiveInteger(options.concurrency ?? 10, "queue concurrency");
-  const capacity = positiveInteger(options.capacity ?? 10_000, "queue capacity");
+  const capacity = options.capacity ?? Number.POSITIVE_INFINITY;
+  if (capacity !== Number.POSITIVE_INFINITY) positiveInteger(capacity, "queue capacity");
   const leaseMs = positiveInteger(options.leaseMs ?? 30_000, "queue leaseMs");
   const pollMs = positiveInteger(options.pollMs ?? 250, "queue pollMs");
   let sequence = 0;
@@ -280,12 +282,13 @@ export function createDurableQueue(options: DurableQueueOptions = {}): DurableQu
       }
 
       if (add.idempotencyKey) {
-        const existing = store.findByIdempotencyKey
-          ? await store.findByIdempotencyKey(name, add.idempotencyKey)
-          : (await store.list(name)).find((job) => job.idempotencyKey === add.idempotencyKey);
+        const existing = await store.findByIdempotencyKey(name, add.idempotencyKey);
         if (existing) return existing as Job<T>;
       }
-      if ((store.size ? await store.size() : (await store.list()).length) >= capacity) {
+      if (
+        capacity !== Number.POSITIVE_INFINITY &&
+        (store.size ? await store.size() : (await store.list()).length) >= capacity
+      ) {
         throw new Error(`WRN-QUEUE-CAPACITY: queue capacity of ${capacity} reached`);
       }