fix(everything): add allowed values to resourceType description

The resourceType argument in the resource-prompt was missing a
description of allowed values. Added "must be 'Text' or 'Blob'" to
help automated callers understand the expected input format.

Issue: #3985

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: Will-hxw

src/everything/resources/templates.ts

@@ -25,7 +25,7 @@ export const RESOURCE_TYPES: string[] = [
  * The completion logic matches the input against available resource types.
  */
 export const resourceTypeCompleter = completable(
-  z.string().describe("Type of resource to fetch"),
+  z.string().describe("Type of resource — must be 'Text' or 'Blob'"),
   (value: string) => {
     return RESOURCE_TYPES.filter((t) => t.startsWith(value));
   }