Merge branch 'master' into worktree/dsh-arg-parser

Integrate the Commander adapter with master's headless rework (dsh -p now boots
through AppCLIEntry — the same cordis.yml composition as dsh web, web-observable
while it runs — via toFetchHandler(ctx.apiProxy)).

- headless.ts: keep master's AppCLIEntry-based body but take the adapter's
  pre-parsed `task` (drop the re-added parseArgs). Old startHost path and the
  now-deleted packages/host/runtime dependency are gone.
- remove the stale packages/host/runtime dir left on disk by master's deletion
  (mirrors the earlier packages/ui/acp cleanup).

vitest.config.ts

@@ -124,6 +124,7 @@ export default defineConfig({
         'packages/client/connection/src/http-bridge.ts',
         'packages/host/apiproxy/src/index.ts',
         'packages/host/apiproxy/src/invariant.ts',
+        'packages/host/apiproxy/src/api-proxy.ts',
         ...windowsUnsupportedPackages.map(path => `${path}/src/**/*.ts`),
         ...windowsCoverageExclusions,
       ],