fix(docker): widen chown prune to the entire hermes-agent path

PR #2470 introduces a `:ro` mount for the `hermes-agent-src` named volume
on the WebUI side of `docker-compose.{two,three}-container.yml`. The
WebUI's docker_init.bash unconditionally runs `chown_home_hermeswebui`
which walks `/home/hermeswebui` with `find -exec chown -h {} +`,
pruning only `/home/hermeswebui/.hermes/hermes-agent/.git/objects` (the
narrow #2237 fix for macOS bind mounts).

With the new `:ro` mount, every other file inside the hermes-agent
subtree is also on a read-only filesystem.  `chown` returns `EROFS`,
`find -exec ... +` propagates the non-zero exit, and the wrapping
`chown_home_hermeswebui || error_exit "..."` under `set -e` kills the
container before the WebUI server can run.

Verified locally:

    $ /usr/bin/find /tmp/ftest -exec false {} +
    $ echo $?
    1

So `find` does propagate `-exec` command failures, which the existing
`|| error_exit` then catches.

The WebUI never writes to the agent source — `uv pip install
/home/hermeswebui/.hermes/hermes-agent` is a pure read.  So aligning
ownership inside the agent subtree was always a nicety, not a
requirement.  Widen the prune to skip the entire
`/home/hermeswebui/.hermes/hermes-agent` path.  This also subsumes the
original #2237 case (the `.git/objects` packs are inside the now-pruned
subtree) without needing a separate carve-out.

Test updates:

- Renamed `test_home_chown_skips_hermes_agent_git_objects` →
  `test_home_chown_skips_hermes_agent_subtree`, and pinned the broader
  prune target (`-path ".../hermes-agent" -prune`).
- Added `test_home_chown_helper_documents_readonly_mount_compat` so a
  future maintainer narrowing the prune back to `.git/objects` (and
  re-introducing the EROFS failure mode) trips a regression.

Verified:

- `tests/test_issue2237_docker_chown_git_objects.py` 4/4 pass.
- `tests/test_docker_docs_and_readonly.py` 9/9 pass.
- Full suite: 5738 passed, 0 failed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docker_init.bash

@@ -185,8 +185,17 @@ chown_home_hermeswebui() {
   # macOS Docker bind mounts can expose hermes-agent git object packs as
   # read-only host files. The runtime only needs to read those existing objects;
   # requiring chown on them makes startup fail before WebUI can run (#2237).
+  #
+  # Multi-container compose (#2470) additionally mounts the entire
+  # hermes-agent-src volume read-only on the WebUI side because the WebUI only
+  # reads it for `uv pip install`. On a :ro mount, chown returns EROFS for any
+  # file inside the subtree, which would propagate to `set -e` and kill startup
+  # before the WebUI can run. Either way, the WebUI never writes to the agent
+  # source — prune the entire hermes-agent path from the chown walk so a
+  # read-only or partially-read-only mount doesn't break the rest of the home
+  # ownership alignment.
   find /home/hermeswebui \
-    -path "/home/hermeswebui/.hermes/hermes-agent/.git/objects" -prune \
+    -path "/home/hermeswebui/.hermes/hermes-agent" -prune \
     -o -exec chown -h "${WANTED_UID}:${WANTED_GID}" {} +
 }