Salvages #24490 by @liuhao1024 against current main.
The Docker daemon will silently auto-create a directory at the host
path of any `-v <host>:<container>` bind mount when the host path
doesn't exist. In Docker-in-Docker setups (where the outer host's
real credential file isn't visible inside the agent's parent
container), this leaves a directory at the credential mount source —
and the inner `docker run` then refuses to mount a directory over a
file destination with exit 125.
Add defensive shape guards to all three mount loops in
DockerEnvironment.__init__:
* credentials (expected: file) — skip + warn on directory or missing
* skills (expected: dir) — skip + warn when not a directory
* cache (expected: dir) — skip + warn when not a directory
Failed mounts surface as WARN logs rather than crashing the container
start. Existing well-formed sources mount unchanged.
The original PR's branch was on a pre-container-reuse-rework base
(May 12) and conflicted with the post-May-28 driver work (label
tagging, container reuse, orphan reaper). Reconstructed the same
intent on current main; the three guard blocks slot cleanly into
`tools/environments/docker.py` around the existing mount loops.
Three new tests pinned in `tests/tools/test_docker_environment.py`:
directory-source skip, missing-source skip, valid-file mounts. Test-
first regression verification: reverted just the production code to
`origin/main` and confirmed the new tests fail with
`'deleted_token.json' is contained here: /root/.hermes/...` — the
fixed code makes them pass. Full file passes (54/54).
Closes#24490
Co-authored-by: liuhao1024 <11816344+liuhao1024@users.noreply.github.com>