Add Bruno API collection for device cap management

- Update User Max Devices - Complete API documentation
- Update User Max Devices - Success test case
- Update User Max Devices - Invalid Zero test case
- Update User Max Devices - Exceeds Maximum test case
- Update User Max Devices - Missing ID test case
- Include validation rules and example payloads
- Document all status codes and error responses

bruno/user/admin/Update User Max Devices - Success.bru

@@ -0,0 +1,32 @@
+meta {
+  name: Update User Max Devices - Success
+  type: http
+  seq: 1
+}
+
+put {
+  url: {{base_url}}/api/auth/users/{{user_id}}/max-devices
+  body: {
+    max_devices: 5
+  }
+  auth: inherit
+}
+
+settings {
+  encodeUrl: true
+  timeout: 0
+}
+
+vars {
+  user_id: 123e4567-e89b-12d3-a456-426614174000
+  max_devices: 5
+}
+
+docs {
+  ## Update User Max Devices - Success Case
+
+  Successfully updates a user's max devices limit to 5.
+
+  **Expected:** 200 OK
+  **Response:** `{"message": "max devices updated"}`
+}