Add a status field indicating if a server is deprecated or active (#210)

The following PR adds a new server `status` field to support the status
of servers, like deprecated or active

Details:
* Add status field to server.json schema with 'active' and 'deprecated'
values
* Update OpenAPI spec to include status field in Server responses
* Add ServerStatus enum and field to Go model structs
* Update examples to demonstrate status field usage (`active` and
`deprecated`)

Since this is my first PR there's a good chance I might have missed
something so I'll appreciate any feedback to make this and any PRs in
the future easier for you to review 😃

Fixes: #181

## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
The main goal is to have a way for server authors to notify registry
consumers that a server may no longer be maintained and shouldn't be
considered for using.

## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->

## Breaking Changes
<!-- Will users need to update their code or configurations? -->

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [ ] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->

---------

Signed-off-by: Radoslav Dimitrov <radoslav@stacklok.com>
Co-authored-by: Tadas Antanavicius <tadas@tadasant.com>

docs/server-registry-api/examples.md

@@ -17,6 +17,7 @@ GET /v0/servers?limit=5000&offset=0
       "id": "a5e8a7f0-d4e4-4a1d-b12f-2896a23fd4f1",
       "name": "io.modelcontextprotocol/filesystem",
       "description": "Node.js server implementing Model Context Protocol (MCP) for filesystem operations.",
+      "status": "active",
       "repository": {
         "url": "https://github.com/modelcontextprotocol/servers",
         "source": "github",
@@ -49,6 +50,7 @@ GET /v0/servers/a5e8a7f0-d4e4-4a1d-b12f-2896a23fd4f1?version=0.0.3
   "id": "a5e8a7f0-d4e4-4a1d-b12f-2896a23fd4f1",
   "name": "io.modelcontextprotocol/filesystem",
   "description": "Node.js server implementing Model Context Protocol (MCP) for filesystem operations.",
+  "status": "active",
   "repository": {
     "url": "https://github.com/modelcontextprotocol/servers",
     "source": "github",
@@ -143,6 +145,7 @@ API Response:
   "id": "brave-search-12345",
   "name": "io.modelcontextprotocol/brave-search",
   "description": "MCP server for Brave Search API integration",
+  "status": "active",
   "repository": {
     "url": "https://github.com/modelcontextprotocol/servers",
     "source": "github",
@@ -195,6 +198,7 @@ API Response:
   "id": "filesystem-67890",
   "name": "io.modelcontextprotocol/filesystem",
   "description": "Node.js server implementing Model Context Protocol (MCP) for filesystem operations",
+  "status": "active",
   "repository": {
     "url": "https://github.com/modelcontextprotocol/servers",
     "source": "github",
@@ -268,6 +272,7 @@ API Response:
   "id": "remote-fs-54321",
   "name": "Remote Brave Search Server",
   "description": "Cloud-hosted MCP Brave Search server",
+  "status": "active",
   "repository": {
     "url": "https://github.com/example/remote-fs",
     "source": "github",

docs/server-registry-api/openapi.yaml

@@ -109,6 +109,12 @@ components:
         description:
           type: string
           example: "Node.js server implementing Model Context Protocol (MCP) for filesystem operations."
+        status:
+          type: string
+          enum: [active, deprecated]
+          default: active
+          description: "Server lifecycle status. 'deprecated' indicates the server is no longer recommended for new usage."
+          example: "active"
         repository:
           $ref: '#/components/schemas/Repository'
         version_detail: