Fix Neo4j auth: disable auth for demo deployment (NEO4J_AUTH=none), simplify entrypoint

Fix 500: use 'or' fallback for env vars, guard eligible-patient query against Neo4j not ready

Fix 502: retry Neo4j connection at startup, delay backend 50s to wait for Neo4j

Initial deployment: ClinicalMatch AI v2.0 — FHIR R4 · MCP (9 tools) · A2A workflow · SHARP compliance · 100k synthetic patients · Neo4j graph · GraphRAG chatbot