Add 'profile' query parameter in cloud-init metadata handlers

[bmcdonald3]

Description

Add query parameter as phase 1 of OpenCHAMI/roadmap#121.

This covers the following routes as specified in the RFD:

GET /cloud-init/meta-data?profile=...
GET /cloud-init/user-data?profile=...
GET /cloud-init/vendor-data?profile=...
GET /cloud-init/{group}.yaml?profile=...

Corresponding changes to boot service and a new node service to follow.

Testing:

cd ~/metadata-service
unset SMD_URL
go run . serve --port 8080
2026/01/30 16:05:44 Starting github.com/OpenCHAMI/cloud-init server...
2026/01/30 16:05:44 File storage initialized in ./data
{"level":"warn","time":"2026-01-30T16:05:44-08:00","message":"SMD_URL not configured, using mock SMD client for development"}
{"level":"info","time":"2026-01-30T16:05:44-08:00","message":"Mock SMD client initialized with sample data including EthernetInterface info"}
2026/01/30 16:05:44 Server starting on 0.0.0.0:8080

Since we are running locally with a fresh ./data directory, we must create the group record so the service has a template to serve. We use the generated CLI client for this.

# Create the 'compute' group with a dummy template
go run ./cmd/client --server http://localhost:8080 group create --spec '{"name":"compute", "template":"#cloud-config\n# Final Verification"}'
{
  "apiVersion": "v1",
  "kind": "Group",
  "schemaVersion": "v1",
  "metadata": {
    "name": "compute",
    "uid": "gro-f7dcc09f",
    "createdAt": "2026-01-30T16:07:40.427895-08:00",
    "updatedAt": "2026-01-30T16:07:40.427895-08:00"
  },
  "spec": {
    "template": "#cloud-config\n# Final Verification"
  },
  "status": {
    "valid": true,
    "currentTemplateVersion": "v-10c16567",
    "templateHistory": [
      {
        "version": "v-10c16567",
        "timestamp": "2026-01-31T00:07:40Z",
        "valid": true
      }
    ]
  }
}

We simulate a request from a known mock node (10.252.0.26) and request a specific profile (staging). We verify that the profile query parameter is preserved in the returned #include URLs.

curl -v -H "X-Forwarded-For: 10.252.0.26" "http://localhost:8080/vendor-data?profile=staging"
#include
/compute.yaml?profile=staging
/green.yaml?profile=staging

Seeing ?profile=staging in the response confirms this change works as expected.