fix: add start-hermes.sh baked into image, replace broken ENTRYPOINT

- New start-hermes.sh: multi-profile launcher that works with s6-overlay's
  main-program model (replaces bash->tini->entrypoint.sh chain)
- Dockerfile: COPY start-hermes.sh into /usr/local/bin/ alongside
  run-multi-gateways.sh (which is now unused but kept for reference)
- compose.yml: remove entrypoint override, CMD now points at
  /usr/local/bin/start-hermes.sh via the image default ENTRYPOINT

Fixes the SIGTERM crash loop caused by S6_CMD_ARG0 being unset when the
deprecated entrypoint.sh shim bypassed s6-overlay's /init.

ai/hermes/Dockerfile

@@ -62,6 +62,11 @@ PYEOF
 # Launches one gateway process per profile (HERMES_PROFILES env var)
 COPY --chmod=0755 run-multi-gateways.sh /usr/local/bin/run-multi-gateways.sh
 
+# ---------- Install s6-overlay compatible startup script ----------
+# Runs as the CMD via s6-overlay's main-program model.
+# Replaces the old bash->tini->entrypoint.sh chain that caused SIGTERM crash loops.
+COPY --chmod=0755 start-hermes.sh /usr/local/bin/start-hermes.sh
+
 # ---------- Runtime ----------
 USER hermes
 ENV HERMES_HOME=/opt/data