remove legacy LangGraph code path

Delete the unused LangGraph runtime, its profiler assets, and the now-unused LangChain dependencies so the main branch only ships the Burr implementation.

Author: ethenotethan

README.md

@@ -163,16 +163,6 @@ This is useful for:
 - Monitoring API usage and performance
 - Learning how the multi-agent system orchestrates tasks
 
-### Live Observability Monitor
-
-For real-time visual monitoring of agent execution with interactive profiling:
-
-```bash
-./observability/live_monitor.sh
-```
-
-This launches a web-based profiler that automatically tracks your current session, displaying tool calls, timing metrics, and agent interactions in real-time. The visualization updates live as your agents work, providing an interactive dashboard for monitoring pipeline execution and performance analysis.
-
 The pipeline will:
 1. Scan for services (Cargo.toml, go.mod, package.json, pyproject.toml files)
 2. Build dependency graph