Full offline test suite for all core modules:
- test_graph_engine: pure-function tests for _compute_causal_chain and
_build_triple; file-reading tests for get_causal_chains and
infer_hidden_relationships; mocked integration tests for run_graph_update
- test_agents: dict_to_string, all calculator tools, router routing logic,
run_agent_query end-to-end with mocked InferenceClient
- test_summary_engine: generate() LLM/fallback/quota paths, get_latest(),
generate_brief_markdown() rule-based and LLM paths
- test_integration_pipeline: end-to-end score_text -> insert -> graph update
Also fixes BFS bug in infer_hidden_relationships: [start] + suffix[1:]
was stripping intermediate nodes, collapsing A->B->C into [A,C] and
preventing any path of length >= 3 from being detected.
81 tests pass, 6 Astra DB integration tests skip without token.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
