fix(security): require proof that x-9r-real-ip came from the socket (GHSA-pjm4-8fpg-f9p6)

x-9r-real-ip and the Host fallback were trusted from client-controlled
headers whenever custom-server.js was not in the request path (npm run
start, start:bun), letting a remote caller pose as local to skip API key
auth and reach LOCAL_ONLY_PATHS (/api/mcp/*, /api/tunnel/enable,
/api/auth/reset-password).

custom-server.js now generates a per-process secret at boot and stamps it
as x-9r-peer-token on every request it sanitizes. hasTrustedPeerHeaders()
(src/lib/auth/trustedPeer.js) gates trust in x-9r-real-ip on that secret;
otherwise the guard falls back to Host only in development, and fails
closed in production. Same gate on loginLimiter.getClientIp() so a spoofed
header cannot rotate the login lockout bucket.

Also: fix isLoopbackHostname for IPv6 (::1, ::ffff:127.0.0.1) which the
old split(":")[0] reduced to empty string; route npm run start /
start:bun through custom-server.js (postbuild copies it into
.next/standalone, build-cli.js fails without it) so documented deployments
keep passwordless local access.

cli/scripts/build-cli.js

@@ -216,7 +216,9 @@ function buildCliPackage() {
     fs.copyFileSync(customServerSrc, path.join(cliAppDir, "custom-server.js"));
     console.log("✅ Copied custom-server.js\n");
   } else {
-    console.warn("⚠️  custom-server.js not found — server will run without real-IP injection\n");
+    console.error("❌ custom-server.js not found — without it no request can be proven local,");
+    console.error("   so the packaged CLI would demand an API key for its own dashboard and /v1.");
+    process.exit(1);
   }
 
   // Step 3b: Ensure sql.js (pure JS fallback) bundled in app/cli/app/node_modules.