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/side-channel/index.d.ts

@@ -0,0 +1,14 @@
+import getSideChannelList from 'side-channel-list';
+import getSideChannelMap from 'side-channel-map';
+import getSideChannelWeakMap from 'side-channel-weakmap';
+
+declare namespace getSideChannel {
+	type Channel<K, V> =
+		| getSideChannelList.Channel<K, V>
+		| ReturnType<Exclude<typeof getSideChannelMap<K, V>, false>>
+		| ReturnType<Exclude<typeof getSideChannelWeakMap<K, V>, false>>;
+}
+
+declare function getSideChannel<K, V>(): getSideChannel.Channel<K, V>;
+
+export = getSideChannel;