Fix is_latest flag management in UpdateServer method

The UpdateServer method was incorrectly using is_latest=true in the WHERE clause
when trying to mark servers as not latest, causing a logic conflict. Changed to
use server_id and version to target the specific record instead.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: tadasant

internal/database/postgres.go

@@ -307,14 +307,26 @@ func (db *PostgreSQL) UpdateServer(ctx context.Context, id string, server *apiv0
 	var args []interface{}
 
 	if hasServerID {
-		// New schema: update by server_id and is_latest
+		// New schema: update by server_id and version to target specific record
+		// We need to find the record by server_id and version from the updated server data
+		serverVersion := ""
+		if server.Version != "" {
+			serverVersion = server.Version
+		} else {
+			// Extract version from the server data if not provided separately
+			var tempServer apiv0.ServerJSON
+			if err := json.Unmarshal(valueJSON, &tempServer); err == nil {
+				serverVersion = tempServer.Version
+			}
+		}
+		
 		query = `
 			UPDATE servers 
 			SET value = $1
 			WHERE server_id = $2
-			AND (value->'_meta'->'io.modelcontextprotocol.registry/official'->>'is_latest')::boolean = true
+			AND (value->>'version') = $3
 		`
-		args = []interface{}{valueJSON, id}
+		args = []interface{}{valueJSON, id, serverVersion}
 	} else {
 		// Old schema: update by id in JSON
 		query = `

internal/service/registry_service.go

@@ -241,10 +241,21 @@ func (s *registryServiceImpl) markAsNotLatest(ctx context.Context, server *apiv0
 		return nil
 	}
 
-	// Update the existing server to set is_latest = false
-	server.Meta.Official.IsLatest = false
-	server.Meta.Official.UpdatedAt = time.Now()
-	_, err := s.db.UpdateServer(ctx, serverID, server)
+	// Create a copy of the server to avoid modifying the original
+	serverCopy := *server
+	if serverCopy.Meta == nil {
+		serverCopy.Meta = &apiv0.ServerMeta{}
+	}
+	if serverCopy.Meta.Official == nil {
+		serverCopy.Meta.Official = &apiv0.RegistryExtensions{}
+	}
+
+	// Update the copy to set is_latest = false
+	serverCopy.Meta.Official.IsLatest = false
+	serverCopy.Meta.Official.UpdatedAt = time.Now()
+	
+	// Use UpdateServer with the serverID which should match the current latest version
+	_, err := s.db.UpdateServer(ctx, serverID, &serverCopy)
 	return err
 }