chore(sdk): genericize appToken comment (no private-product references) (#29)

Core is open source; the appToken schema comment named a private downstream
hook/file. Describe the behavior generically — a multi-tenant host uses the
token to route the install to the right tenant; single-tenant deployments
ignore it. No functional change.

Author: onamfc

src/routes/sdk.ts

@@ -58,8 +58,8 @@ export async function sdkRoutes(fastify: FastifyInstance) {
       sdkName: z.string().max(50).optional(),
       sdkVersion: z.string().max(50).optional(),
       // Public app token shipped in SDK app bundles to scope organic
-      // installs to the right org in multi-tenant deployments. Used by
-      // Cloud's onSend hook (see cloud-event-hook.ts). Self-hosted
+      // installs to the right org in multi-tenant deployments. A multi-tenant
+      // host reads it to route the install to the correct tenant; self-hosted
       // single-tenant deployments simply ignore it.
       appToken: z.string().optional(),
     });