Save in-progress keysat integration and StartOS 0.4 work

Snapshot of the working tree before cleanup. Captures:
- Keysat licensing: server/license.js, /api/license/* endpoints in
  server/index.js, activation modal in public/index.html, embedded
  Ed25519 issuer key (assets/issuer.pub).
- StartOS 0.4 expansion: setApiKey action, version files v0.1.1
  through v0.1.15, file-models/config.json.ts, manifest updates.
- Self-hosted registry server (startos-registry/).
- Build/deploy scripts (bin/bump-version.sh, bin/deploy.sh, vendored
  yt-dlp binary), .gitignore, .deploy.env.example.
- Recent design docs (KEYSAT_INTEGRATION.md, UPGRADE-DESIGN.md) —
  retained here so they remain recoverable when removed in the
  follow-up cleanup commit.

startos-registry/node_modules/cookie-signature/index.js

@@ -0,0 +1,51 @@
+/**
+ * Module dependencies.
+ */
+
+var crypto = require('crypto');
+
+/**
+ * Sign the given `val` with `secret`.
+ *
+ * @param {String} val
+ * @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
+ * @return {String}
+ * @api private
+ */
+
+exports.sign = function(val, secret){
+  if ('string' !== typeof val) throw new TypeError("Cookie value must be provided as a string.");
+  if (null == secret) throw new TypeError("Secret key must be provided.");
+  return val + '.' + crypto
+    .createHmac('sha256', secret)
+    .update(val)
+    .digest('base64')
+    .replace(/\=+$/, '');
+};
+
+/**
+ * Unsign and decode the given `val` with `secret`,
+ * returning `false` if the signature is invalid.
+ *
+ * @param {String} val
+ * @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
+ * @return {String|Boolean}
+ * @api private
+ */
+
+exports.unsign = function(val, secret){
+  if ('string' !== typeof val) throw new TypeError("Signed cookie string must be provided.");
+  if (null == secret) throw new TypeError("Secret key must be provided.");
+  var str = val.slice(0, val.lastIndexOf('.'))
+    , mac = exports.sign(str, secret);
+  
+  return sha1(mac) == sha1(val) ? str : false;
+};
+
+/**
+ * Private
+ */
+
+function sha1(str){
+  return crypto.createHash('sha1').update(str).digest('hex');
+}