Add OpenTelemetry tracing instrumentation

[rbarbadillo]

Summary

• add OpenTelemetry tracing hooks for SDK requests, responses, streaming responses, and API errors
• expose observability helpers to register a tracer provider and create manual spans
• keep @opentelemetry/api as an optional peer dependency and persist dependency metadata in Speakeasy config
• run SDK HTTP sends with the GenAI span as the active OpenTelemetry context, so auto-instrumented HTTP/fetch spans parent correctly (avoids Fix OTEL parenting for HTTPX spans client-python#557)
• normalize streamed completion chunks before tracing enrichment so nullable optional fields or missing finish_reason do not drop the first output chunk

Usage

import { Mistral } from "@mistralai/mistralai";
import { registerTracerProvider } from "@mistralai/mistralai/extra/observability";
import { NodeTracerProvider } from "@opentelemetry/sdk-trace-node";

const provider = new NodeTracerProvider();

// Configure processors/exporters here if needed.
// provider.addSpanProcessor(...)

provider.register();
registerTracerProvider(provider);

const client = new Mistral({
  apiKey: process.env.MISTRAL_API_KEY,
});

const response = await client.chat.complete({
  model: "mistral-small-latest",
  messages: [{ role: "user", content: "Hello" }],
});