fix(docker): detect and refresh stale build-artefact volumes

codeman-node-modules and codeman-dist (docker-compose.yaml) are seeded
from the image only while empty, so a rebuilt image's fresh dist/
node_modules sat unused behind old volume content until something
cleared it. The in-app self-updater never hit this (it rebuilds INSIDE
the running container, into the very volume already in use), but a
`docker compose build` triggered from outside it — Start-Codeman.sh,
after a manual `git pull` — did: the container came back up looking
unchanged, serving stale compiled routes against current source.

Start-Codeman.sh now compares the checkout's HEAD commit and
package-lock.json hash against a recorded marker
(docker-build-source.json) and clears just the affected volume(s)
before its own --build when either moved.

The in-place self-update path writes that same marker after a
successful build, so the two mechanisms agree on what the volumes
currently reflect — without it, the next plain Start-Codeman.sh run
would see the HEAD self-update just checked out, not recognise it as
already accounted for, and wipe the volumes self-update just correctly
rebuilt right back to the older baked image.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01R9ZSTEenc8soSu9bTi8Xru

docker/Start-Codeman.sh

@@ -106,6 +106,26 @@ if [[ ! -d "$repo_path/.git" ]]; then
   printf 'Note: %s is not a git checkout, so in-app updates are unavailable.\n' "$repo_path" >&2
 fi
 
+# Reads HEAD without requiring a `git` binary on the host — this script
+# otherwise checks the checkout only by testing for `.git` as a directory, and
+# resolving refs by hand keeps that the same "no host git needed" guarantee.
+git_head_commit() {
+  local git_dir="$1/.git" head_ref ref_path
+  [[ -d "$git_dir" ]] || return 1
+  head_ref=$(cat -- "$git_dir/HEAD" 2>/dev/null) || return 1
+  if [[ "$head_ref" == ref:* ]]; then
+    ref_path="${head_ref#ref: }"
+    if [[ -f "$git_dir/$ref_path" ]]; then
+      cat -- "$git_dir/$ref_path"
+    else
+      # Packed after a `git gc`; the loose ref file above is gone.
+      awk -v ref="$ref_path" '$2 == ref { print $1; exit }' "$git_dir/packed-refs" 2>/dev/null
+    fi
+  else
+    printf '%s' "$head_ref"
+  fi
+}
+
 # Record what the container is about to be built and created FROM. The in-app
 # updater compares these against the release it wants to apply: a release that
 # changes either file cannot be applied by the container restarting itself (a
@@ -140,4 +160,50 @@ else
   printf 'Warning: no sha256 tool found; in-app updates will not detect environment changes.\n' >&2
 fi
 
+# codeman-node-modules and codeman-dist (docker-compose.yaml) are seeded from
+# the image only while EMPTY, so a rebuilt image's fresh output sits unused
+# behind old volume content until something clears it. The in-app self-updater
+# never hits this — it rebuilds INSIDE the running container, into the very
+# volume already in use — but a `docker compose build` triggered from outside
+# it (this script, after a `git pull`) does: the container comes back up
+# looking unchanged. Detect that here and clear just the affected volume(s) so
+# `--build` below actually takes effect. Best-effort: with no sha256 tool this
+# quietly does nothing, same as the environment-gate block above.
+if [[ -n "$dockerfile_sha" ]]; then
+  repo_head=$(git_head_commit "$repo_path" || true)
+  lockfile_sha=$(sha256_of "$repo_path/package-lock.json" 2>/dev/null || true)
+  source_state_file="$state_dir/docker-build-source.json"
+  prev_head=''
+  prev_lockfile_sha=''
+  if [[ -f "$source_state_file" ]]; then
+    prev_head=$(sed -n 's/.*"headCommit": *"\([^"]*\)".*/\1/p' "$source_state_file")
+    prev_lockfile_sha=$(sed -n 's/.*"lockfileSha256": *"\([^"]*\)".*/\1/p' "$source_state_file")
+  fi
+
+  volumes_to_refresh=()
+  [[ -n "$repo_head" && "$repo_head" != "$prev_head" ]] && volumes_to_refresh+=('codeman-dist')
+  [[ -n "$lockfile_sha" && "$lockfile_sha" != "$prev_lockfile_sha" ]] && volumes_to_refresh+=('codeman-node-modules')
+
+  if [[ ${#volumes_to_refresh[@]} -gt 0 ]]; then
+    # Runs even on this script's very first invocation against an EXISTING
+    # deployment, deliberately: that deployment's volumes may already be
+    # stale (there was no earlier version of this check to have caught it),
+    # and clearing an already-empty or nonexistent volume is a harmless
+    # no-op, so there is no fresh-install case this needs to avoid.
+    printf 'Source changed since the last start; refreshing: %s\n' "${volumes_to_refresh[*]}"
+    "${compose_command[@]}" down
+    for key in "${volumes_to_refresh[@]}"; do
+      volume_name=$(docker volume ls -q --filter "label=com.docker.compose.volume=$key" | head -n1)
+      [[ -n "$volume_name" ]] && docker volume rm -- "$volume_name"
+    done
+  fi
+
+  printf '{\n  "headCommit": "%s",\n  "lockfileSha256": "%s"\n}\n' \
+    "$repo_head" "$lockfile_sha" >"$source_state_file.tmp"
+  mv -- "$source_state_file.tmp" "$source_state_file"
+  if [[ "$EUID" == '0' ]]; then
+    chown -- "$PUID:$PGID" "$source_state_file"
+  fi
+fi
+
 exec "${compose_command[@]}" up --build -d