Sentry integration for error tracking

[ibrahimcesar]

Description

Integrate with Sentry to correlate telemetry events with error reports.

Features

• Automatic error context enrichment
• Telemetry event → Sentry breadcrumbs
• Sentry event → Telemetry correlation
• Shared user context (anonymous)

Example Usage

```rust
TelemetryKit::builder()
.service_name("my-app")
.with_sentry(sentry::init(...))
.build()?;

// Errors automatically include telemetry context
```

Benefits

• Understand what users did before errors
• Correlate feature usage with error rates
• Privacy-preserving error context

Acceptance Criteria

• Optional Sentry feature flag
• Bidirectional context sharing
• No additional PII exposure