feat(cli): expose region option on the MCP trigger_task tool

Adds a `region` field to the `trigger_task` MCP tool's options so a run
can be triggered in a specific region, overriding the project default.
The value is passed straight through to the trigger API, which already
accepts it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GwLsz4J3EwF9EMSpLY6LAC

Author: claude

.changeset/mcp-trigger-task-region.md

@@ -0,0 +1,5 @@
+---
+"trigger.dev": patch
+---
+
+You can now choose the region a run executes in when triggering a task through the MCP server.

docs/mcp-tools.mdx

@@ -61,7 +61,7 @@ Get the current worker for a project, including the worker version, SDK version,
 
 ### trigger_task
 
-Trigger a task to run with a specific payload. You can add a delay, set tags, configure retries, choose a machine size, set a TTL, or use an idempotency key.
+Trigger a task to run with a specific payload. You can add a delay, set tags, configure retries, choose a machine size, pick a region, set a TTL, or use an idempotency key.
 
 **Example usage:**
 - `"Run the email-notification task"`

packages/cli-v3/src/mcp/schemas.ts

@@ -100,6 +100,12 @@ export const TriggerTaskInput = CommonProjectsInput.extend({
         .number()
         .describe("The maximum duration in seconds of the task run")
         .optional(),
+      region: z
+        .string()
+        .describe(
+          "The region to run the task in, overriding the default region set for the project. Available regions are listed on the Regions page in the dashboard, and this has no effect in the dev environment"
+        )
+        .optional(),
       tags: z
         .array(z.string())
         .describe(