docs: queue examples drop the deprecated concurrencyLimit field, intro cards split

The Queues page's queue() examples no longer set concurrencyLimit (marked
deprecated in the SDK in favor of the task concurrency option, and not
needed for ordering); the tasks overview example uses concurrency instead
of the deprecated inline queue option; the introduction card grid links
Queues and Concurrency separately.

Author: matt-aitken

docs/introduction.mdx

@@ -71,8 +71,11 @@ We provide everything you need to build and manage background tasks: a CLI and S
   >
     Learn how to handle errors and retries.
   </Card>
-  <Card title="Concurrency & Queues" icon="line-height" href="/concurrency" color="#D946EF">
-    Configure what you want to happen when there is more than one run at a time.
+  <Card title="Concurrency" icon="line-height" href="/concurrency" color="#D946EF">
+    Limit how many runs execute at once: per task, per tenant, or shared across tasks.
+  </Card>
+  <Card title="Queues" icon="layer-group" href="/queues" color="#D946EF">
+    Control the order your runs execute in.
   </Card>
   <Card
     title="Wait for token (human-in-the-loop)"

docs/queues.mdx

@@ -16,10 +16,7 @@ Declare a queue with `queue()` and set it on several tasks to interleave their r
 ```ts /trigger/emails.ts
 import { queue, task } from "@trigger.dev/sdk";
 
-const emailQueue = queue({
-  name: "emails",
-  concurrencyLimit: 5,
-});
+const emailQueue = queue({ name: "emails" });
 
 export const sendWelcomeEmail = task({
   id: "send-welcome-email",
@@ -52,10 +49,7 @@ When you trigger a task you can override its queue by name. This is really usefu
 ```ts /trigger/override-queue.ts
 import { queue, task } from "@trigger.dev/sdk";
 
-const paidQueue = queue({
-  name: "paid-users",
-  concurrencyLimit: 10,
-});
+const paidQueue = queue({ name: "paid-users" });
 
 export const generatePullRequest = task({
   id: "generate-pull-request",

docs/tasks/overview.mdx

@@ -98,16 +98,14 @@ For more information read [the retrying guide](/errors-retrying).
 
 It's also worth mentioning that you can [retry a block of code](/errors-retrying) inside your tasks as well.
 
-### `queue` options
+### `queue` and `concurrency` options
 
-Queues control the order your runs execute in, and pair with concurrency limits for one-at-a-time execution, parallel executions, and more advanced techniques like separate concurrency for different sets of your users. For more information read the [Queues](/queues) and [Concurrency](/concurrency) guides.
+Queues control the order your runs execute in, and concurrency limits control how many execute at once: one-at-a-time execution, parallel executions, and more advanced techniques like separate concurrency for different sets of your users. For more information read the [Queues](/queues) and [Concurrency](/concurrency) guides.
 
 ```ts /trigger/one-at-a-time.ts
 export const oneAtATime = task({
   id: "one-at-a-time",
-  queue: {
-    concurrencyLimit: 1,
-  },
+  concurrency: { total: 1 },
   run: async (payload: any, { ctx }) => {
     //...
   },