M3b plan: task 11 gives Podman::egress_dir(), so the field is read

Without it the field was never read in task 11, clippy's dead_code failed the
gate, and #[allow] is forbidden; the implementer stopped on the dilemma.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/plans/M3b/README.md

@@ -65,6 +65,10 @@ At the end: `make gate` prints `gate: ok` with about 638 tests.
   `egress-proxy` never matched; and `serve` joined each handler thread, serving one connection at a
   time. The attempt is saved in `.state/runs/M3b/08-first-attempt.diff`; the tree was reset, and the
   task now says both things explicitly and to debug inside the repository. Resume from task 08.
+- 2026-09-23, task 11: the session ended in deliberation, with nothing written. The task stored
+  `egress_dir` for task 12 but gave nothing that read it, so clippy's `dead_code` would fail the
+  gate and `#[allow]` is forbidden: a task that could not be written as described (tip T16). The
+  reference had a public `egress_dir()` getter; the task now gives it. Resume from task 11.
 
 ## Running it