Sovereign Nexus: Add L402 Server Skeleton

l402_server.py

@@ -0,0 +1,35 @@
+
+#!/usr/bin/env python3
+from http.server import HTTPServer, BaseHTTPRequestHandler
+import json
+import secrets
+
+class L402Handler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        if self.path == '/api/cost-estimate':
+            # Simulate L402 Challenge
+            macaroon = secrets.token_hex(16)
+            invoice = "lnbc1..." # Mock invoice
+            
+            self.send_response(402)
+            self.send_header('WWW-Authenticate', f'L402 macaroon="{macaroon}", invoice="{invoice}"')
+            self.send_header('Content-type', 'application/json')
+            self.end_headers()
+            
+            response = {
+                "error": "Payment Required",
+                "message": "Please pay the invoice to access cost estimation."
+            }
+            self.wfile.write(json.dumps(response).encode())
+        else:
+            self.send_response(404)
+            self.end_headers()
+
+def run(server_class=HTTPServer, handler_class=L402Handler, port=8080):
+    server_address = ('', port)
+    httpd = server_class(server_address, handler_class)
+    print(f"Starting L402 Skeleton Server on port {port}...")
+    httpd.serve_forever()
+
+if __name__ == "__main__":
+    run()