Clean up dead demos and restructure directory layout

Phase 1 - Remove dead/duplicate content:
- Delete demos/samples_java/ (incomplete Java demo)
- Delete demos/shared/chatbot_ui/ (replaced by AnythingLLM)
- Delete demos/shared/grafana/, prometheus/, logfire/, honeycomb/, signoz/
  (legacy observability stacks; only jaeger is retained)
- Delete variant docker-compose files (honeycomb, logfire, signoz, jaeger)
- Delete demos/use_cases/spotify_bearer_auth/run_demo.sh (stale script)

Phase 2 - Restructure into semantic categories:
- getting_started/  : weather_forecast, llm_gateway
- agent_orchestration/ : travel_agents, multi_agent_crewai_langchain
- llm_routing/       : model_alias_routing, preference_based_routing, claude_code_router
- filter_chains/     : http_filter, mcp_filter
- integrations/      : ollama, spotify_bearer_auth
- advanced/          : model_choice_test_harness, multi_turn_rag,
                       currency_exchange, stock_quote

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

demos/samples_python/multi_turn_rag_agent/main.py

@@ -1,42 +0,0 @@
-import os
-import gradio as gr
-
-from fastapi import FastAPI, HTTPException
-from pydantic import BaseModel
-from typing import Optional
-from openai import OpenAI
-
-app = FastAPI()
-
-
-# Define the request model
-class EnergySourceRequest(BaseModel):
-    energy_source: str
-    consideration: Optional[str] = None
-
-
-class EnergySourceResponse(BaseModel):
-    energy_source: str
-    consideration: Optional[str] = None
-
-
-# Post method for device summary
-@app.post("/agent/energy_source_info")
-def get_workforce(request: EnergySourceRequest):
-    """
-    Endpoint to get details about energy source
-    """
-    considertion = "You don't have any specific consideration. Feel free to talk in a more open ended fashion"
-
-    if request.consideration is not None:
-        considertion = f"Add specific focus on the following consideration when you summarize the content for the energy source: {request.consideration}"
-
-    response = {
-        "energy_source": request.energy_source,
-        "consideration": considertion,
-    }
-    return response
-
-
-if __name__ == "__main__":
-    app.run(debug=True)