Introduce the foundational observability layer for the sync pipeline:
- MetricsLayer: Custom tracing subscriber layer that captures span timing
and structured fields, materializing them into a hierarchical
Vec<StageTiming> tree for robot-mode performance data output
- logging: Dual-layer subscriber infrastructure with configurable stderr
verbosity (-v/-vv/-vvv) and always-on JSON file logging with daily
rotation and configurable retention (default 30 days)
- SyncRunRecorder: Compile-time enforced lifecycle recorder for sync_runs
table (start -> succeed|fail), with correlation IDs and aggregate counts
- LoggingConfig: New config section for log_dir, retention_days, and
file_logging toggle
- get_log_dir(): Path helper for log directory resolution
- is_permanent_api_error(): Distinguish retryable vs permanent API failures
(only 404 is truly permanent; 403/auth errors may be environmental)
Database changes:
- Migration 013: Add resource_events_synced_for_updated_at watermark columns
to issues and merge_requests tables for incremental resource event sync
- Migration 014: Enrich sync_runs with run_id correlation ID, aggregate
counts (total_items_processed, total_errors), and run_id index
- Wrap file-based migrations in savepoints for rollback safety
Dependencies: Add uuid (run_id generation), tracing-appender (file logging)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>