docs(readme): clarify embedding model seed order for Neo4j indexes

Document that the system embedding model must be seeded before running
`setup_neo4j_indexes`, since vector index dimensions are read from the
`llm_manager_llmmodel` row. Update Docker instructions to reflect the
`init` sidecar behavior, which now runs migrations and library_type
defaults automatically while deferring vector index creation.

mnemosyne/docker/entrypoint.sh

@@ -0,0 +1,111 @@
+#!/bin/sh
+# Mnemosyne container entrypoint.
+#
+# The same image runs all three processes — the compose service supplies
+# `web`, `mcp`, `worker`, or `migrate` as CMD.
+
+set -e
+
+case "$1" in
+  web)
+    # Django REST API + admin (gunicorn → wsgi).
+    exec gunicorn \
+      --config /app/docker/gunicorn.conf.py \
+      --bind 0.0.0.0:8000 \
+      --workers "${GUNICORN_WORKERS:-3}" \
+      --access-logfile - \
+      --error-logfile - \
+      mnemosyne.wsgi:application
+    ;;
+
+  mcp)
+    # FastMCP over Streamable HTTP at /mcp/, mounted by mnemosyne.asgi.
+    exec uvicorn \
+      --host 0.0.0.0 \
+      --port 8001 \
+      --workers "${UVICORN_WORKERS:-1}" \
+      mnemosyne.asgi:app
+    ;;
+
+  worker)
+    # Celery worker covering embedding + ingest + batch + default queues.
+    # In production you may want to split these onto separate worker
+    # services for queue-level isolation; one process is fine to start.
+    exec celery -A mnemosyne worker \
+      --loglevel="${CELERY_LOG_LEVEL:-info}" \
+      --queues="${CELERY_QUEUES:-celery,embedding,batch}" \
+      --concurrency="${CELERY_CONCURRENCY:-2}"
+    ;;
+
+  beat)
+    # Celery scheduled tasks (only needed if/when periodic jobs are wired).
+    exec celery -A mnemosyne beat \
+      --loglevel="${CELERY_LOG_LEVEL:-info}"
+    ;;
+
+  migrate)
+    # One-shot DB migration runner — invoke before bringing services up
+    # for the first time or after a deploy.
+    exec python manage.py migrate --noinput
+    ;;
+
+  setup)
+    # One-shot init — Neo4j indexes + library_type seed data.
+    python manage.py setup_neo4j_indexes
+    python manage.py load_library_types
+    ;;
+
+  init)
+    # Bundled one-shot init run by the `init` sidecar on every
+    # `docker compose up`. Idempotent: re-runs are no-ops unless
+    # migrations or library-type seed data need to change.
+    #
+    # Vector-index creation intentionally runs in *best-effort* mode:
+    # ``setup_neo4j_indexes`` requires a system embedding model with a
+    # configured ``vector_dimensions`` value, and that model is data an
+    # operator seeds via the admin UI after the stack comes up for the
+    # first time. Blocking the whole stack on first boot would force
+    # every new deployer through a manual dance with the init sidecar's
+    # entrypoint; instead we log loudly and carry on, and the operator
+    # runs the command once post-boot:
+    #
+    #     docker compose exec app python manage.py setup_neo4j_indexes
+    #
+    # Full-text and neomodel constraint indexes are created by the same
+    # command and are *not* dimension-sensitive, but they also only land
+    # after the operator re-runs it — acceptable because search against
+    # an empty graph is itself a no-op.
+    set -e
+    python manage.py migrate --noinput
+    python manage.py load_library_types
+    if ! python manage.py setup_neo4j_indexes; then
+      echo ""
+      echo "============================================================"
+      echo "NOTICE: Neo4j index creation was skipped."
+      echo ""
+      echo "This is expected on a fresh deployment — vector indexes"
+      echo "require a system embedding model with vector_dimensions set."
+      echo ""
+      echo "Seed the embedding model in the Django admin"
+      echo "  (/admin/llm_manager/llmmodel/, mark one row as"
+      echo "   is_system_embedding_model=True with vector_dimensions set),"
+      echo "then run:"
+      echo ""
+      echo "  docker compose exec app python manage.py setup_neo4j_indexes"
+      echo ""
+      echo "Search endpoints will return empty results until this is done."
+      echo "============================================================"
+      echo ""
+    fi
+    ;;
+
+  shell)
+    # Drop into the management shell for ad-hoc work.
+    exec python manage.py shell
+    ;;
+
+  *)
+    # Fall through: run whatever was passed (e.g. `manage.py <cmd>`).
+    exec "$@"
+    ;;
+esac