AR10.9 / AR03.1: full docker rm reverse synthesis (DR-CR-22)

[espadonne]

Summary

• AR10.9 / DR-CR-22 — lands the full docker rm reverse path that AR03.1 was blocked on. ```docker rm -f ``` now round-trips name + image-source + env + ports + mounts + restart policy + in-place rootfs writes.
• Helper side: `prepare_rm` runs `docker inspect` to capture the container config as JSON, detects `.State.Running`, and `docker commit`s running containers to a `shit-stash--` tag so rootfs edits survive the rm.
• Planner side: new pure function `synthesize_container_run` walks the inspect JSON and produces `docker run -d` argv with ~15 options. `apply_rm` is rewritten from the stage-1 `Skipped` stub to parse JSON, verify the stash image still exists, swap `.Config.Image` for the stash tag, and exec the synthesized argv.
• Smoke: launches busybox with port/env/volume/restart-policy + writes a probe file to the rootfs via `docker exec`. Asserts post-undo container has the same effective config AND the probe file (proving the stash-commit preserves in-place writes).

Argv synthesis coverage

15 options: `--name`, image (stash or original), `-d`, `-e`, `-p host:container/proto`, `-v` (volume + bind + ro mode), `--tmpfs`, `--restart=policy[:n]`, `--network` (omits "default"), `--privileged`, `--read-only`, `--cap-add`/`--cap-drop`, `--hostname` (skipped if auto-generated from container id), `-u`, `-w`, `--label`, `--entrypoint` (joined with spaces), `Cmd` (positional after image).

Deferred: GPU runtime detection (DR-CR-30), IPC/PID/UTS namespaces, resource limits (`--memory`, `--cpus`, `--shm-size`). Captured inspect JSON is always available via `shit show` for the user to fill in manually.

Test plan

• `cargo build --workspace --release` green
• `cargo fmt --all -- --check` clean
• `cargo clippy --workspace --all-targets --all-features -- -D warnings` clean
• `cargo test -p shit-planner --lib executors::container` — 38 tests pass (10 existing + 28 new synthesizer + apply_rm rewrite tests)
• `cargo test -p shit-helper --bin shit-helper container::event` — 8 tests pass (added inspect-helper + warn-fallback tests)
• `dr-smoke / docker-rm-undo` job green (validates port + env + mount + restart + rootfs-probe round-trip)
• No regressions on docker-rmi-undo (AR03.2), docker-volume-rm-undo (AR03.3), docker-network-rm-undo (AR03.4)
• `linux-kernel-capture` matrix stays green