fix(entrypoint): docker-compose env overrides win over OpenBao-fetched values

The previous entrypoint unconditionally exported every key from
kv/ped-ai/prod. This broke the e2e container, which needs
TURNSTILE_SECRET_KEY="" and SMTP_HOST="" set via docker-compose
environment block so login works without bot challenge and register
auto-verifies. OpenBao's real values were overriding those empties,
re-enabling Turnstile and email on e2e.

Fix: before the OpenBao fetch, snapshot every env var name already
defined (env_file + environment: block). During the export loop,
skip any OpenBao key that's already in the snapshot. Docker-compose
wins, OpenBao fills in the rest.

Impact:
- Prod container: no change (env_file only has OPENBAO_* bootstrap
  vars, which aren't in the KV payload anyway)
- E2e container: TURNSTILE_SECRET_KEY="" and SMTP_HOST="" preserved
  even when the image is rebuilt from the current source tree
- Any future per-container override via docker-compose environment:
  block just works

Log line now reports counts: "applied N secrets; M already set by
docker (kept override)".

docker-entrypoint.sh

@@ -38,9 +38,34 @@ if [ -n "${OPENBAO_ADDR:-}" ]; then
     exit 1
   fi
 
-  # Export each key/value as a shell-safe env var.
-  # jq's @sh filter single-quote-escapes values so eval is safe.
-  eval "$(printf '%s' "${SECRET_JSON}" | jq -r 'to_entries[] | "export \(.key)=\(.value | @sh)"')"
+  # Export each key/value as a shell-safe env var — but ONLY if the key
+  # isn't already set by docker (env_file / environment: block). This
+  # lets a docker-compose override win over the OpenBao value, which is
+  # needed for e2e (TURNSTILE_SECRET_KEY="" / SMTP_HOST="") and any
+  # environment-specific override.
+  #
+  # Pattern: write jq output to a temp file, then while-read in the main
+  # shell so exports persist (pipes into while run in a subshell and lose
+  # them). Pre-snapshot env keys and skip those already defined.
+  _PRESET_KEYS_FILE=$(mktemp)
+  env | cut -d= -f1 | sort -u > "$_PRESET_KEYS_FILE"
+
+  _SECRET_ASSIGNS=$(mktemp)
+  printf '%s' "${SECRET_JSON}" | jq -r 'to_entries[] | "\(.key)\t\(.value | @sh)"' > "$_SECRET_ASSIGNS"
+
+  _APPLIED_COUNT=0
+  _SKIPPED_COUNT=0
+  while IFS="$(printf '\t')" read -r _K _VAL_QUOTED; do
+    if [ -z "$_K" ]; then continue; fi
+    if grep -qxF "$_K" "$_PRESET_KEYS_FILE"; then
+      _SKIPPED_COUNT=$((_SKIPPED_COUNT + 1))
+    else
+      eval "export $_K=$_VAL_QUOTED"
+      _APPLIED_COUNT=$((_APPLIED_COUNT + 1))
+    fi
+  done < "$_SECRET_ASSIGNS"
+  rm -f "$_PRESET_KEYS_FILE" "$_SECRET_ASSIGNS"
+  echo "[entrypoint]   applied ${_APPLIED_COUNT} secrets; ${_SKIPPED_COUNT} already set by docker (kept override)"
 
   # Bootstrap credentials are no longer needed in the Node process env.
   unset OPENBAO_ROLE_ID OPENBAO_SECRET_ID BAO_TOKEN