fix: port 8080 conflict between L402 server and preview (#1415)

- L402 server: port configurable via L402_PORT env var (default 8080)
- app.js: L402 URL reads ?l402_port= from query string
- mempalace example: changed port from 8080 to 7772

Fixes #1415.

app.js

@@ -15,6 +15,10 @@ import { ReasoningTrace } from './nexus/components/reasoning-trace.js';
 // NEXUS v1.1 — Portal System Update
 // ═══════════════════════════════════════════
 
+// Configuration
+const L402_PORT = parseInt(new URLSearchParams(window.location.search).get('l402_port') || '8080');
+const L402_URL = `http://localhost:${L402_PORT}/api/cost-estimate`;
+
 const NEXUS = {
   colors: {
     primary:    0x4af0c0,
@@ -681,7 +685,7 @@ function updateGOFAI(delta, elapsed) {
     
     // Simulate calibration update
     calibrator.update({ input_tokens: 100, complexity_score: 0.5 }, 0.06);
-    if (Math.random() > 0.95) l402Client.fetchWithL402("http://localhost:8080/api/cost-estimate");
+    if (Math.random() > 0.95) l402Client.fetchWithL402(L402_URL);
   }
   
   metaLayer.track(startTime);

l402_server.py

@@ -3,6 +3,7 @@
 from http.server import HTTPServer, BaseHTTPRequestHandler
 import json
 import secrets
+import os
 
 class L402Handler(BaseHTTPRequestHandler):
     def do_GET(self):
@@ -25,7 +26,9 @@ class L402Handler(BaseHTTPRequestHandler):
             self.send_response(404)
             self.end_headers()
 
-def run(server_class=HTTPServer, handler_class=L402Handler, port=8080):
+def run(server_class=HTTPServer, handler_class=L402Handler, port=None):
+    if port is None:
+        port = int(os.environ.get('L402_PORT', 8080))
     server_address = ('', port)
     httpd = server_class(server_address, handler_class)
     print(f"Starting L402 Skeleton Server on port {port}...")

mempalace/fleet_api.py

@@ -27,7 +27,7 @@ Usage:
     python mempalace/fleet_api.py
 
     # Custom host/port/palace:
-    FLEET_PALACE_PATH=/data/fleet python mempalace/fleet_api.py --host 0.0.0.0 --port 8080
+    FLEET_PALACE_PATH=/data/fleet python mempalace/fleet_api.py --host 0.0.0.0 --port 7772
 
 Refs: #1078, #1075, #1085
 """