Add Human-in-the-Loop (HITL) support in Lungo

[shkurapa]

Description

This PR introduces a Human-in-the-Loop (HITL) system for the Lungo auction supervisor, enabling human oversight for high-stakes order decisions using LangGraph's interrupt() capability.

Overview

The HITL system uses two specialized models to determine when and how to involve humans in the decision-making process:

1. WHEN-TO-TRIGGER Model - Analyzes user queries to detect scenarios requiring human review (budget constraints, missing parameters, market volatility)
2. WHAT-TO-RESPOND Model - Generates actionable scenarios and recommendations for human selection

Key Features

• LangGraph Interrupts: Pauses graph execution when human intervention is needed, resuming with the user's decision
• Dynamic Scenario Generation: Generates context-aware allocation scenarios based on order parameters
• Pluggable Model Architecture: Abstract base classes allow easy replacement of mock models with real inference
• Full UI Integration: New sidebar section and interactive scenario selection component

New Files

Backend:

• agents/supervisors/auction/graph/hitl.py - Model interfaces and mock implementations
• agents/supervisors/auction/graph/graph_hitl.py - HITL-enabled LangGraph with interrupt nodes
• agents/supervisors/auction/api_hitl.py - REST endpoints for HITL workflow (/agent/prompt/hitl, /agent/prompt/hitl/resume)

Frontend:

• frontend/src/hooks/useHITLAPI.ts - React hook for HITL API interactions
• frontend/src/components/Chat/HITLScenarios.tsx - Scenario display and selection component

Modified Files

• agents/supervisors/auction/main.py - Include HITL router
• frontend/src/App.tsx - HITL state management
• frontend/src/components/Chat/ChatArea.tsx - HITL flow integration
• frontend/src/components/Sidebar/Sidebar.tsx - New "Human-in-the-Loop" navigation section
• frontend/src/utils/patternUtils.ts - Added PUBLISH_SUBSCRIBE_HITL pattern

Graph Flow

SUPERVISOR
    ├── INVENTORY_SINGLE_FARM → REFLECTION → END
    ├── INVENTORY_ALL_FARMS → REFLECTION → END
    ├── ORDERS → TRIGGER_EVALUATION
    │              ├── [TRIGGER] → RESPONSE_GENERATION → HUMAN_INTERVENTION
    │              │                                          ↓
    │              │                              PROCESS_HUMAN_DECISION → END
    │              └── [NO_TRIGGER] → ORDERS_TOOLS → REFLECTION → END
    └── GENERAL_INFO → END

Example Usage

Prompt: I need to place our Q2 order. 500 lbs total, budget capped at $2,000. What are our options?

The system:

1. Detects budget constraint, missing origin, and potential budget exceedance
2. Generates 4 allocation scenarios (Budget-Optimized, Quality-First, Balanced Diversilected scenario and confirms the order

Testing

Select "Human-in-the-Loop > A2A NATS (HITL)" in the sidebar and try the example prompt above.