v0 plan: task 04 timeout check needs --preserve-status; note the finding

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/plans/v0/04-admin-main.md

@@ -94,11 +94,11 @@ cp docs/plans/v0/_files/internal/admin/admin_test.go internal/admin/
 
 ```sh
 make build
-timeout --signal=TERM 3 bin/crossbar -config example.toml; echo "exit=$?"
+timeout --preserve-status --signal=TERM 3 bin/crossbar -config example.toml; echo "exit=$?"
 ```
 
 Expected on stderr: a line containing `listening` and `addr=127.0.0.1:17777`, then
-`shutting down`; then `exit=0`. (`example.toml` names two upstreams that are not running; the
+`shutting down`; then `exit=0` (`--preserve-status` makes `timeout` report crossbar's own exit code; without it GNU `timeout` prints 124 for any child it had to signal). (`example.toml` names two upstreams that are not running; the
 health table simply records them unhealthy — that is fine here.)
 
 ```sh

docs/plans/v0/README.md

@@ -69,3 +69,8 @@ stops at the first task that does not end with a commit, a clean tree and a `don
   investigating instead of editing the Makefile. Fixed by moving the directory to `_files/`
   (directories starting with `_` are ignored by the go tool); every task file updated. Task 01
   restarted from a clean tree.
+- 2026-09-25, task 04: the step-5 check `timeout --signal=TERM 3 bin/crossbar …; echo $?` expected
+  `exit=0`, but GNU `timeout` reports 124 whenever it had to signal the child, whatever the child's
+  own exit status. Ornith noticed, sent SIGTERM directly, confirmed exit 0 that way, logged the
+  deviation and finished. Task-text fault (case: my task, not the model); fixed with
+  `--preserve-status`.