feat(F-158): completed feature

work/artifacts/F-158/security.json

@@ -0,0 +1,14 @@
+{
+  "feature_id": "F-158",
+  "agent": "security",
+  "stage": "security_gate",
+  "verdict": "APPROVED",
+  "summary": "La URL backend queda server-only y las cookies de sesión/terminal se mantienen HttpOnly y same-origin.",
+  "checks": [
+    { "item": "Backend URL not public", "ok": true, "evidence": "POS_BACKEND_URL is only read in server route handler" },
+    { "item": "Terminal cookie protection", "ok": true, "evidence": "HttpOnly, SameSite=Lax, Secure in production" },
+    { "item": "Fixed upstream host", "ok": true, "evidence": "Client controls path only; upstream base comes from trusted env" },
+    { "item": "No broad header forwarding", "ok": true, "evidence": "Only cookie, content-type and x-terminal-id forwarded" }
+  ],
+  "issues": []
+}