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).

tsconfig.host.json

@@ -143,7 +143,6 @@
     { "path": "./packages/hooks/hooks-codex" },
     { "path": "./packages/mcp/mcp-client" },
     { "path": "./packages/host/apiproxy" },
-    { "path": "./packages/host/runtime" },
     { "path": "./packages/host/webserver" },
     { "path": "./packages/sdk/helper" },
     { "path": "./packages/sdk/scripts" },