feat: tunnel TS exports, port forward labels, and db migrations

- Add TS derive and type annotations to all tunnel API param structs
- Export tunnel bindings to a tunnel/ subdirectory with index generation
- Change port forward label from String to Option<String>
- Add TunnelDatabase::init() with default subnet creation
- Add tunnel migration framework with m_00_port_forward_entry migration
  to convert legacy string-only port forwards to the new entry format

sdk/base/lib/osBindings/ServerInfo.ts

@@ -26,7 +26,7 @@ export type ServerInfo = {
   zram: boolean
   governor: Governor | null
   smtp: SmtpValue | null
-  ifconfigUrl: string
+  echoipUrls: string[]
   ram: number
   devices: Array<LshwDevice>
   kiosk: boolean | null