chore: standardize configuration, logging, and error handling across blockchain node and coordinator API

- Add infrastructure.md and workflow files to .gitignore to prevent sensitive info leaks
- Change blockchain node mempool backend default from memory to database for persistence
- Refactor blockchain node logger with StructuredLogFormatter and AuditLogger (consistent with coordinator)
- Add structured logging fields: service, module, function, line number
- Unify coordinator config with Database

docs/3_miners/6_monitoring.md

@@ -0,0 +1,110 @@
+# Monitoring & Alerts
+Monitor your miner performance and set up alerts.
+
+## Real-time Monitoring
+
+### Dashboard
+
+```bash
+aitbc miner dashboard
+```
+
+Shows:
+- GPU utilization
+- Memory usage
+- Temperature
+- Active jobs
+- Earnings rate
+
+### CLI Stats
+
+```bash
+aitbc miner stats
+```
+
+### Prometheus Metrics
+
+```bash
+# Enable metrics endpoint
+aitbc miner metrics --port 9090
+```
+
+Available at: http://localhost:9090/metrics
+
+## Alert Configuration
+
+### Set Alerts
+
+```bash
+# GPU temperature alert
+aitbc miner alert --metric temp --threshold 85 --action notify
+
+# Memory usage alert
+aitbc miner alert --metric memory --threshold 90 --action throttle
+
+# Job failure alert
+aitbc miner alert --metric failures --threshold 3 --action pause
+```
+
+### Alert Types
+
+| Type | Description |
+|------|-------------|
+| temp | GPU temperature |
+| memory | GPU memory usage |
+| utilization | GPU utilization |
+| jobs | Job success/failure rate |
+| earnings | Earnings below threshold |
+
+### Alert Actions
+
+| Action | Description |
+|--------|-------------|
+| notify | Send notification |
+| throttle | Reduce job acceptance |
+| pause | Stop accepting jobs |
+| restart | Restart miner |
+
+## Log Management
+
+### View Logs
+
+```bash
+# Recent logs
+aitbc miner logs --tail 100
+
+# Filter by level
+aitbc miner logs --level error
+
+# Filter by job
+aitbc miner logs --job-id <JOB_ID>
+```
+
+### Log Rotation
+
+```bash
+# Configure log rotation
+aitbc miner logs --rotate --max-size 100MB --keep 5
+```
+
+## Health Checks
+
+```bash
+# Run health check
+aitbc miner health
+
+# Detailed health report
+aitbc miner health --detailed
+```
+
+Shows:
+- GPU health
+- Driver status
+- Network connectivity
+- Storage availability
+
+## Next
+
+- [Quick Start](./1_quick-start.md) — Get started
+- [GPU Setup](./5_gpu-setup.md) — GPU configuration
+- [Job Management](./3_job-management.md) — Job management