gamma-observability

# Gamma Observability

## Overview
Implement comprehensive monitoring, logging, and tracing for Gamma integrations.

## Prerequisites
- Observability stack (Prometheus, Grafana, or cloud equivalent)
- Log aggregation (ELK, CloudWatch, or similar)
- APM tool (Datadog, New Relic, or OpenTelemetry)

## Three Pillars of Observability

### 1. Metrics

```typescript
// lib/gamma-metrics.ts
import { Counter, Histogram, Gauge, Registry } from 'prom-client';

const registry = new Registry();

// Request metrics
const requestCounter = new Counter({
  name: 'gamma_requests_total',
  help: 'Total Gamma API requests',
  labelNames: ['method', 'endpoint', 'status'],
  registers: [registry],
});

const requestDuration = new Histogram({
  name: 'gamma_request_duration_seconds',
  help: 'Gamma API request duration',
  labelNames: ['method', 'endpoint'],
  buckets: [0.1, 0.5, 1, 2, 5, 10, 30],
  registers: [registry],
});

// Business metrics
const presentationsCreated = new Counter({
  name: 'gamma_presentations_created_total',
  help: 'Total presentations created',
  labelNames: ['style', 'user_tier'],
  registers: [registry],
});

const rateLimitRemaining = new Gauge({
  name: 'gamma_rate_limit_remaining',
  help: 'Remaining API calls in rate limit window',
  registers: [registry],
});

// Instrumented client
export function createInstrumentedClient() {
  return new GammaClient({
    apiKey: process.env.GAMMA_API_KEY,
    interceptors: {
      request: (config) => {
        config._startTime = Date.now();
        return config;
      },
      response: (response, config) => {
        const duration = (Date.now() - config._startTime) / 1000;
        const endpoint = config.path.split('/')[1];

        requestCounter.inc({
          method: config.method,
          endpoint,
          status: response.status,
        });

        requestDuration.observe(
          { method: config.method, endpoint },
          duration
        );

        // Update rate limit gauge
        const rem