feat: offer delete or remap when server is gone from cloud provider (#2641)

* feat: offer delete or remap when server is gone from cloud provider

When a user tries to connect to a server that no longer exists, instead
of silently marking it as deleted, present an interactive picker that
lets them remap the history entry to an existing instance on the same
cloud or explicitly remove it from history.

- Add listServers() to Hetzner, DigitalOcean, AWS, and GCP providers
- Add updateRecordConnection() to history for remapping server details
- Add handleGoneServer() interactive flow in list.ts
- Fall back to silent deletion in non-interactive mode (SPAWN_NON_INTERACTIVE)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor: move InstancesListSchema to module level

Declare valibot schema at module top level per project convention,
not inside the listServers() function body.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor: extract shared CloudInstance type from duplicated inline types

The { id, name, ip, status } shape was declared inline 9 times across
5 files. Extract it as a shared CloudInstance interface in history.ts
and import it in all cloud providers and list.ts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude <claude@anthropic.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@openrouter/spawn",
-  "version": "0.18.5",
+  "version": "0.18.6",
   "type": "module",
   "bin": {
     "spawn": "cli.js"