fix(authz): derive LOCAL_ONLY locality from Host header (middleware has no socket IP)

The authz pipeline runs in the Next middleware runtime (proxy.ts -> runAuthzPipeline)
where ctx.request is a NextRequest with no .socket/.ip. requestPeerAddress therefore
returned null, so isLoopbackRequest was ALWAYS false and every LOCAL_ONLY path 403'd
even from loopback (Services/MCP/Traffic-Inspector were unusable). Read the Host
header instead — exactly what isLoopbackHost/isPrivateLanHost were built to parse —
which restores loopback and, combined with isPrivateLanHost, enables the
owner-authorized private-LAN access. Spawn-capable endpoints still require
manage-scope auth after this gate.

src/server/authz/policies/management.ts

@@ -19,7 +19,16 @@ import {
 const MODEL_SYNC_MANAGEMENT_PATH = /^\/api\/providers\/[^/]+\/(sync-models|models)$/;
 
 function requestPeerAddress(ctx: PolicyContext): string | null {
-  return ctx.request.ip || ctx.request.socket?.remoteAddress || null;
+  // In the Next middleware runtime (proxy.ts → runAuthzPipeline), ctx.request is
+  // a NextRequest with no socket/.ip, so the only locality signal is the Host
+  // header — which is exactly what isLoopbackHost/isPrivateLanHost parse (they
+  // strip :port). This both fixes the loopback gate (previously the null socket
+  // made every LOCAL_ONLY request 403, even from localhost) and enables the
+  // owner-authorized private-LAN carve-out. Fall back to .ip/.socket for any
+  // non-middleware caller that provides them. Spawn-capable endpoints still
+  // require manage-scope auth after this gate.
+  const hostHeader = ctx.request.headers?.get?.("host") ?? null;
+  return hostHeader || ctx.request.ip || ctx.request.socket?.remoteAddress || null;
 }
 
 function isLoopbackRequest(ctx: PolicyContext): boolean {

tests/unit/route-guard-private-lan.test.ts

@@ -1,5 +1,7 @@
 import test from "node:test";
 import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
 import { isPrivateLanHost, isLoopbackHost, isLocalOnlyPath } from "../../src/server/authz/routeGuard.ts";
 
 test("isPrivateLanHost: accepts RFC1918 IPv4 (incl. :port and ::ffff: mapped)", () => {
@@ -45,3 +47,11 @@ test("services + traffic-inspector remain LOCAL_ONLY paths", () => {
   assert.equal(isLocalOnlyPath("/api/services/9router/status"), true);
   assert.equal(isLocalOnlyPath("/api/tools/traffic-inspector/sessions"), true);
 });
+
+test("management policy derives locality from the Host header (middleware socket is null)", () => {
+  const src = readFileSync(
+    join(import.meta.dirname, "../../src/server/authz/policies/management.ts"),
+    "utf8"
+  );
+  assert.ok(src.includes('headers?.get?.("host")'), "requestPeerAddress must read the Host header");
+});