OpenTelemetry 1P Events

What: First-party event logging using OpenTelemetry protocol Details:

• Exports events to Anthropic's event logging endpoint: {ANTHROPIC_BASE_URL}/api/event_logging/batch
• New exporter class IB0 at line 477676 handles batching and export
• Transforms logs into ClaudeCodeInternalEvent format with environment context
• Logger initialization in or2() at line 477773 with automatic shutdown handling
• Controlled by feature gate tengu_log_1p_events (gate check in rr2() at line 477755)
• Events include session context, environment details, and custom metadata
• Evidence: IB0 class at lines 477676-477751, initialization or2() at line 477773, event emission ZB0() at line 477761