Auto-load prior DSG into Neo4j on chatdsg startup

[harelb]

Fixes MIT-SPARK/Awesome-DCIST-T4#337.

Problem

1. The load path was broken. chatdsg.py called load_dsg_to_db() with the old five-argument signature (object_labelspace, room_labelspace, uri, creds, graph), but heracles.utils.load_dsg_to_db() takes (neo4j_uri, neo4j_creds, scene_graph) and reads labelspaces from the graph metadata. Passing --scene-graph raised TypeError.
2. Nothing ever triggered a load. The dcist launch components invoke ./chatdsg.py with no arguments and the load was gated on if args.scene_graph:, so the prior scene graph was never loaded.
3. The example was coupled to the embedding stack. chatdsg.py read ADT4_HERACLES_IP/ADT4_HERACLES_PORT and agent_config.yaml built its Neo4j URI from the same pair, so the example could not be configured without ADT4-specific variables. heracles/docker/docker-compose.yaml had to set them alongside the HERACLES_* ones it already provides.

Changes

• Fixed the load_dsg_to_db() call and removed --object-labelspace / --room-labelspace. Labelspaces come from the graph; extract_labelspaces_from_dsg() warns when one carries none rather than silently loading unlabeled objects and rooms.
• Configuration is HERACLES_* only. --db_ip/--db_port are replaced by --neo4j-uri, defaulting to $HERACLES_NEO4J_URI — the name heracles' own load_scene_graph.py uses and that docker-compose.yaml already sets. Credentials come from HERACLES_NEO4J_USERNAME/PASSWORD. The cypher tool's uri is $HERACLES_NEO4J_URI.
• The scene graph path comes only from --scene-graph; the deployment supplies it. nargs="?" is gone, since a valueless flag behaved identically to omitting the argument.
• Added --no-dsg-load, because loading calls initialize_db(), which clears the database — so a load on every startup wipes Neo4j. There is an existing feature/chatdsg_optional_dsg_reset branch suggesting the same need.
• logging.basicConfig() so startup messages print before the Textual app takes the terminal.
• Missing URI or credentials skips the load with a warning instead of producing a half-initialized startup.

Companion change

MIT-SPARK/Awesome-DCIST-T4 supplies the path and translates its variables into the HERACLES_* names, which is that repo's job:

• launch_components/heracles_prior_dsg.yaml runs ./chatdsg.py --scene-graph $ADT4_PRIOR_MAP/hydra/backend/dsg.json
• base_launch/base_launch.yaml exports HERACLES_NEO4J_URI and HERACLES_AGENTS_PATH (it already mapped the credentials and OpenAI key)

Both must land together: with the new launch config against old chatdsg.py, --scene-graph hits the TypeError.

Testing

Against a live Neo4j, with example_dsg.json staged as a prior map.

• With every ADT4_* variable unset and only the HERACLES_* values the launch env now exports: DSG loads (65 objects / 96 2D places / 5 rooms) and LlmAgent constructs successfully.
• Cypher queries confirm labels come from the graph's embedded labelspace, not the YAML files — objects resolve to seating, storage, sign, decor; rooms to hallway, lounge.
• $HERACLES_NEO4J_URI expansion in agent_config.yaml verified through HeraclesDsgInterface (neo4j://127.0.0.1:7687).
• Guard paths: missing DSG file, missing URI, and missing credentials each warn and skip without touching the database. --no-dsg-load skips.
• pre-commit run --all-files clean.

unit-tests.yml has not been run locally.

Note

One ADT4 reference remains in examples/chatdsg/agent_config.yaml: planner_topic: /${ADT4_ROBOT_NAME}/omniplanner_node/..., expanded by the shell inside os.system() in pddl_calling_tool.py. It names a topic on an omniplanner node that only exists in the larger stack, so it is arguably deployment config rather than a leak — but it can be renamed to a HERACLES_* variable for consistency if preferred.

[harelb]

We should have the dcist launch config from adt4 repo pass this in via the commadn line rather than getting the path here.

[harelb]

Done in 70bf92a. Removed PRIOR_DSG_RELPATH and default_scene_graph_path(); the path now comes only from --scene-graph, and nargs="?" is gone since a valueless flag was equivalent to omitting it.

The launch side is MIT-SPARK/Awesome-DCIST-T4 — launch_components/heracles_prior_dsg.yaml now runs:

./chatdsg.py --scene-graph $ADT4_PRIOR_MAP/hydra/backend/dsg.json

regenerated via scripts/generate_configs.sh. Verified with that exact invocation: 65 objects / 96 2D places / 5 rooms loaded, labels from the graph's embedded labelspace. If $ADT4_PRIOR_MAP is unset the pane passes /hydra/backend/dsg.json, which hits the missing-file guard and warns instead of failing.