Init world. Basic registry API server

Work in progress .
This commit adds the core registry service implementation with methods to:
- Retrieve all registry entries
- List entries with cursor-based pagination
- Fetch specific server details by ID

internal/api/router/router.go

@@ -0,0 +1,19 @@
+// Package router contains API routing logic
+package router
+
+import (
+	"net/http"
+
+	"github.com/modelcontextprotocol/registry/internal/config"
+	"github.com/modelcontextprotocol/registry/internal/service"
+)
+
+// New creates a new router with all API versions registered
+func New(cfg *config.Config, registry service.RegistryService) *http.ServeMux {
+	mux := http.NewServeMux()
+
+	// Register routes for all API versions
+	RegisterV0Routes(mux, cfg, registry)
+
+	return mux
+}