Introduce a /version API (#667)

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## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
The following PR introduces a `/version` API that serves the build
details along with the version of the API server being served. The
`/version` endpoint allows users to programmatically query which exact
version of the registry is running in production for debugging.
~~auditing, and compatibility checks~~.

## How Has This Been Tested?
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tested? -->

## Breaking Changes
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## Types of changes
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the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] 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. -->
- [ ] 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
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Signed-off-by: Radoslav Dimitrov <radoslav@stacklok.com>

internal/api/openapi_compliance_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v3"
 
+	v0 "github.com/modelcontextprotocol/registry/internal/api/handlers/v0"
 	"github.com/modelcontextprotocol/registry/internal/api/router"
 	"github.com/modelcontextprotocol/registry/internal/config"
 )
@@ -42,8 +43,15 @@ func TestOpenAPIEndpointCompliance(t *testing.T) {
 		JWTPrivateKey: "0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20", // 32-byte hex key
 	}
 
+	// Create version info for testing
+	versionInfo := &v0.VersionBody{
+		Version:   "test",
+		GitCommit: "test",
+		BuildTime: "test",
+	}
+
 	// Register V0 routes exactly like production does
-	router.RegisterV0Routes(api, cfg, nil, nil) // nil service and metrics for schema testing
+	router.RegisterV0Routes(api, cfg, nil, nil, versionInfo) // nil service and metrics for schema testing
 
 	// Get the OpenAPI schema
 	req := httptest.NewRequest(http.MethodGet, "/openapi.yaml", nil)