refactor: Remove dead code and stale references (#2010)

Dead code removed:
- `cleanup_stale_apps` function in `sh/e2e/lib/cleanup.sh` — defined but
  never called; `e2e.sh` calls `cloud_cleanup_stale` directly instead
- `generateEnvConfig` and `AgentConfig` re-exports from all 7 cloud-specific
  `agents.ts` modules (aws, hetzner, gcp, digitalocean, daytona, local,
  sprite) — nothing imported these from the cloud modules; they were already
  available via `@openrouter/spawn-shared` and `../shared/agents`

All 1435 tests pass, biome lint is clean (0 errors).

Co-authored-by: spawn-qa-bot <qa@openrouter.ai>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@openrouter/spawn",
-  "version": "0.11.7",
+  "version": "0.11.8",
   "type": "module",
   "bin": {
     "spawn": "cli.js"