Charge AI training crawlers for access (@profullstack/x402-gateway)

Training crawlers (GPTBot, ClaudeBot, CCBot, meta-externalagent, Bytespider,
Applebot-Extended) get 402 Payment Required with an x402 offer, or the sales
page at /crawl, and a paid pass opens the site for a day. People, search
engines and retrieval crawlers pass through untouched. robots.txt is now
generated from the same lists.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YafYxayh7Gqe5MWNNQMev2

package-lock.json

@@ -141,6 +141,7 @@
         "@logicsrc/openprd": "file:../../packages/openprd",
         "@profullstack/autoblog": "github:profullstack/autoblog#75e54af",
         "@profullstack/stack": "^0.1.3",
+        "@profullstack/x402-gateway": "^0.1.0",
         "@supabase/supabase-js": "^2.105.4",
         "marked": "^18.0.5",
         "next": "16.2.6",
@@ -2618,6 +2619,15 @@
         }
       }
     },
+    "node_modules/@profullstack/x402-gateway": {
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/@profullstack/x402-gateway/-/x402-gateway-0.1.0.tgz",
+      "integrity": "sha512-B7tWvWk/bIEoqyec6UoyRF1pO7X/+b+wFRv2ZFIClqskmEpyxoA559ZgdTvnxqAIvuDeE9v56nVpYRQ+lmOZQQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=20.11"
+      }
+    },
     "node_modules/@rolldown/binding-android-arm64": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/@rolldown/binding-android-arm64/-/binding-android-arm64-1.0.3.tgz",