feat: include node information in get and list command responses

[dluc]

Summary

Enhances both the get and list commands to include node information in their JSON/YAML responses, allowing users to see which node was used for retrieving the content.

Before (get command):

{
  "id": "sh7lxf0xxkyekj70632czg2c",
  "content": "Call pediatrician for flu shot appointment",
  "mimeType": "text/plain",
  "byteSize": 42,
  ...
}

After (get command):

{
  "id": "sh7lxf0xxkyekj70632czg2c",
  "node": "personal",
  "content": "Call pediatrician for flu shot appointment",
  "mimeType": "text/plain",
  "byteSize": 42,
  ...
}

Before (list command):

{
  "items": [
    {
      "id": "sh7lxf0xxkyekj70632czg2c",
      "content": "...",
      ...
    }
  ],
  "pagination": {...}
}

After (list command):

{
  "items": [
    {
      "id": "sh7lxf0xxkyekj70632czg2c",
      "node": "personal",
      "content": "...",
      ...
    }
  ],
  "pagination": {...}
}

Changes

• Modified GetCommand.cs to wrap result with node information
• Modified ListCommand.cs to wrap each item with node information
• Node information is already available from the Initialize() method
• Maintains all existing fields in the response

Testing

• ✅ All 301 tests pass (192 Main.Tests + 109 Core.Tests)
• ✅ 0 skipped tests
• ✅ Code coverage: 81.99% (exceeds 80% threshold)
• ✅ Build: 0 warnings, 0 errors

Stats

• Files changed: 2
• Lines added: 36
• Lines removed: 2
• Tests added: 0 (existing tests validate behavior)

Breaking Changes

None - this is a backward-compatible enhancement that adds information to the response while maintaining all existing fields.