fix: AIUI proxy graceful error without API key, deploy proxy parity

Claude proxy no longer crashes when ANTHROPIC_API_KEY is not set.
Instead serves a 401 with a helpful message telling users to configure
their API key in Settings. Fixes blank AIUI on fresh installs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/deploy-to-target.sh

@@ -687,6 +687,9 @@ class Handler(http.server.BaseHTTPRequestHandler):
         m = data.get("model", "")
         if m in MODEL_MAP: data["model"] = MODEL_MAP[m]
         body = json.dumps(data).encode()
+        if not API_KEY:
+            err = json.dumps({"type":"error","error":{"type":"auth_error","message":"AIUI not configured. Set your Anthropic API key in Settings > AIUI to enable AI chat."}}).encode()
+            self.send_response(401); self.send_header("Content-Type","application/json"); self.send_header("Content-Length",str(len(err))); self.end_headers(); self.wfile.write(err); return
         headers = {"Content-Type":"application/json","x-api-key":API_KEY,"anthropic-version":"2023-06-01","anthropic-dangerous-direct-browser-access":"true"}
         for h in ["anthropic-version","anthropic-beta"]:
             if self.headers.get(h): headers[h] = self.headers[h]
@@ -716,7 +719,7 @@ class Handler(http.server.BaseHTTPRequestHandler):
             self.send_response(200); self.send_header("Content-Type","application/json"); self.end_headers(); self.wfile.write(b"{\"status\":\"ok\"}")
         else: self.send_response(404); self.end_headers()
     def log_message(self, fmt, *args): pass
-if not API_KEY: print("ERROR: ANTHROPIC_API_KEY not set"); sys.exit(1)
+if not API_KEY: print("WARNING: ANTHROPIC_API_KEY not set — AIUI will return setup instructions")
 server = http.server.HTTPServer(("127.0.0.1", PORT), Handler)
 print(f"Claude API proxy on port {PORT}")
 server.serve_forever()