fix(downgrade): sync README marker references with source

Codex CLI review flagged 2 READMEs still referencing old TODO markers
after source had been updated to XXX:

- packages/bash-local/README.md: TODO(stateful-shell) → XXX(stateful-shell)
- packages/tool-bash/README.md:   TODO(tool-bash-owner-hmr) → XXX(tool-bash-owner-hmr)

packages/bash-local/README.md

@@ -18,7 +18,7 @@ Local-subprocess implementation of the `@deepseek-ai/dsh-bash` executor seam: `L
 
 Design surveyed against the bash tools of Claude Code, OpenCode, Codex, and pi; the notable choices:
 
-- **Spawn per call, no shell state** — every call is a fresh non-login `bash -c` (deterministic; no rc files). All four surveyed tools spawn per call. `TODO(stateful-shell)` in `src/run.ts` records the two proven stateful designs (Claude Code's cwd-only persistence; Codex's PTY exec sessions) for when real workflows demand them.
+- **Spawn per call, no shell state** — every call is a fresh non-login `bash -c` (deterministic; no rc files). All four surveyed tools spawn per call. `XXX(stateful-shell)` in `src/run.ts` records the two proven stateful designs (Claude Code's cwd-only persistence; Codex's PTY exec sessions) for when real workflows demand them.
 - **Process-group kills with escalation** — children are spawned `detached` (own process group); kills send SIGTERM to the group, then SIGKILL after a 3s grace (OpenCode's escalation; pipelines and subshells die with the parent). ESRCH is tolerated; daemons that re-parent away from the group can still survive — same caveat as the surveyed tools.
 - **Tail-keep truncation + spill files** — output beyond `maxOutputBytes` keeps the in-memory TAIL (errors/results cluster at the end — pi/OpenCode rationale) while the FULL stream is appended to a temp file whose path is reported. The model can `grep`/`tail` the spill file with bash itself.
 - **Model-friendly env** — `NO_COLOR=1 TERM=dumb PAGER=cat GIT_PAGER=cat` (Codex's hardcoded set) so pagers and ANSI color don't garble results.