feat: Refactor loongsuite-instrumentation-dify for the latest OTel/LoongSuite semantic conventions.

[Cirilla-zmh]

Semantic conventions:

• OTel GenAI semconv: https://github.com/open-telemetry/semantic-conventions/blob/main/docs/gen-ai/gen-ai-spans.md
• OTel GenAI Agent semconv: https://github.com/open-telemetry/semantic-conventions/blob/main/docs/gen-ai/gen-ai-agent-spans.md
• Entry Span semconv (experimental): Enhancing OTel GenAI Semantic Conventions with a User-Centric Entry Span open-telemetry/semantic-conventions#3418
• ReAct Span semconv (experimental): Adding ReAct Iterations Spans in Reasoning-Acting Agents open-telemetry/semantic-conventions-genai#81