feat: add n8n serve node and harden remote access

- Add the n8n community node package with credentials, command mapping, direct serve TCP client, and browser-cli protocol crypto helpers.

- Cover Ed25519 signing, canonical JSON, PQ transport encryption, request mapping, and security behavior with unit tests.

- Harden serve-http with per-address rate limiting, an 8 MB request body cap, and clear warnings when binding plain HTTP beyond loopback.

- Stop one-shot --key overrides from being persisted automatically; document explicit remote trust and keep key-management behind the keys policy tier.

- Make HTML-to-Markdown conversion safer by bounding tree depth and dropping unsafe link/image URL schemes.

- Bump package and extension release metadata to 0.16.3.

n8n-nodes-browser-cli/nodes/BrowserCli/browserCli.svg

@@ -0,0 +1,31 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128" role="img" aria-labelledby="title">
+  <title>browser-cli icon</title>
+  <defs>
+    <linearGradient id="bg" x1="16" y1="16" x2="112" y2="112" gradientUnits="userSpaceOnUse">
+      <stop offset="0" stop-color="#0f766e" />
+      <stop offset="1" stop-color="#0f172a" />
+    </linearGradient>
+    <linearGradient id="panel" x1="32" y1="29" x2="96" y2="99" gradientUnits="userSpaceOnUse">
+      <stop offset="0" stop-color="#f8fafc" />
+      <stop offset="1" stop-color="#cbd5e1" />
+    </linearGradient>
+  </defs>
+
+  <!-- Chrome Web Store compliant: 96x96 artwork centered in 128x128 canvas. -->
+  <rect x="16" y="16" width="96" height="96" rx="24" fill="url(#bg)" />
+  <rect x="17" y="17" width="94" height="94" rx="23" fill="none" stroke="#ccfbf1" stroke-opacity="0.55" stroke-width="2" />
+
+  <rect x="32" y="31" width="64" height="54" rx="11" fill="url(#panel)" />
+  <path d="M32 42c0-6.075 4.925-11 11-11h42c6.075 0 11 4.925 11 11v3H32z" fill="#94a3b8" />
+  <circle cx="42" cy="38.5" r="2.2" fill="#f8fafc" />
+  <circle cx="49" cy="38.5" r="2.2" fill="#f8fafc" opacity="0.85" />
+  <circle cx="56" cy="38.5" r="2.2" fill="#f8fafc" opacity="0.7" />
+
+  <path d="M49 57 40 64l9 7" fill="none" stroke="#0f172a" stroke-linecap="round" stroke-linejoin="round" stroke-width="7" />
+  <path d="M62 55h17" fill="none" stroke="#0f766e" stroke-linecap="round" stroke-width="7" />
+  <path d="M62 67h23" fill="none" stroke="#0f766e" stroke-linecap="round" stroke-width="7" />
+
+  <rect x="70" y="78" width="22" height="15" rx="5" fill="#14b8a6" />
+  <rect x="59" y="84" width="22" height="15" rx="5" fill="#2dd4bf" />
+  <rect x="48" y="90" width="22" height="15" rx="5" fill="#99f6e4" />
+</svg>