## Summary
Updates the `_meta` field structure to be compliant with the MCP
specification by using proper `prefix/name` format for vendor
extensions.
### Changes
- **Registry metadata**: `io.modelcontextprotocol.registry` →
`io.modelcontextprotocol.registry/official`
- **Publisher metadata**: `publisher` →
`io.modelcontextprotocol.registry/publisher-provided`
- **Database migration**: Updates indexes to use new field paths
- **Updated all code**: Service layer, validators, tests, and seed data
### Format Before
```json
{
"_meta": {
"publisher": { "license": "MIT" },
"io.modelcontextprotocol.registry": { "id": "...", "is_latest": true }
}
}
```
### Format After
```json
{
"_meta": {
"io.modelcontextprotocol.registry/publisher-provided": { "license": "MIT" },
"io.modelcontextprotocol.registry/official": { "id": "...", "is_latest": true }
}
}
```
This resolves the naming collision with the planned top-level
`publisher` field and ensures compliance with MCP specification
requirements.
Fixes#356
ef4607720d