feat: Add enterprise DBA features for production reliability

New features implemented:

1. Backup Catalog (internal/catalog/)
   - SQLite-based backup tracking
   - Gap detection and RPO monitoring
   - Search and statistics
   - Filesystem sync

2. DR Drill Testing (internal/drill/)
   - Automated restore testing in Docker containers
   - Database validation with custom queries
   - Catalog integration for drill-tested status

3. Smart Notifications (internal/notify/)
   - Event batching with configurable intervals
   - Time-based escalation policies
   - HTML/text/Slack templates

4. Compliance Reports (internal/report/)
   - SOC2, GDPR, HIPAA, PCI-DSS, ISO27001 frameworks
   - Evidence collection from catalog
   - JSON, Markdown, HTML output formats

5. RTO/RPO Calculator (internal/rto/)
   - Recovery objective analysis
   - RTO breakdown by phase
   - Recommendations for improvement

6. Replica-Aware Backup (internal/replica/)
   - Topology detection for PostgreSQL/MySQL
   - Automatic replica selection
   - Configurable selection strategies

7. Parallel Table Backup (internal/parallel/)
   - Concurrent table dumps
   - Worker pool with progress tracking
   - Large table optimization

8. MySQL/MariaDB PITR (internal/pitr/)
   - Binary log parsing and replay
   - Point-in-time recovery support
   - Transaction filtering

CLI commands added: catalog, drill, report, rto

All changes support the goal: reliable 3 AM database recovery.

README.md

@@ -16,12 +16,22 @@ Database backup and restore utility for PostgreSQL, MySQL, and MariaDB.
 - AES-256-GCM encryption
 - Incremental backups
 - Cloud storage: S3, MinIO, B2, Azure Blob, Google Cloud Storage
-- Point-in-Time Recovery (PITR) for PostgreSQL
+- Point-in-Time Recovery (PITR) for PostgreSQL and MySQL/MariaDB
 - **GFS retention policies**: Grandfather-Father-Son backup rotation
 - **Notifications**: SMTP email and webhook alerts
 - Interactive terminal UI
 - Cross-platform binaries
 
+### Enterprise DBA Features
+
+- **Backup Catalog**: SQLite-based catalog tracking all backups with gap detection
+- **DR Drill Testing**: Automated disaster recovery testing in Docker containers
+- **Smart Notifications**: Batched alerts with escalation policies
+- **Compliance Reports**: SOC2, GDPR, HIPAA, PCI-DSS, ISO27001 report generation
+- **RTO/RPO Calculator**: Recovery objective analysis and recommendations
+- **Replica-Aware Backup**: Automatic backup from replicas to reduce primary load
+- **Parallel Table Backup**: Concurrent table dumps for faster backups
+
 ## Installation
 
 ### Docker
@@ -257,6 +267,10 @@ dbbackup backup single mydb --dry-run
 | `pitr` | PITR management |
 | `wal` | WAL archive operations |
 | `interactive` | Start interactive UI |
+| `catalog` | Backup catalog management |
+| `drill` | DR drill testing |
+| `report` | Compliance report generation |
+| `rto` | RTO/RPO analysis |
 
 ## Global Flags
 
@@ -478,6 +492,117 @@ dbbackup backup single mydb --notify
 - `cleanup_completed`
 - `verify_completed`, `verify_failed`
 - `pitr_recovery`
+- `dr_drill_passed`, `dr_drill_failed`
+- `gap_detected`, `rpo_violation`
+
+## Backup Catalog
+
+Track all backups in a SQLite catalog with gap detection and search:
+
+```bash
+# Sync backups from directory to catalog
+dbbackup catalog sync /backups
+
+# List recent backups
+dbbackup catalog list --database mydb --limit 10
+
+# Show catalog statistics
+dbbackup catalog stats
+
+# Detect backup gaps (missing scheduled backups)
+dbbackup catalog gaps --interval 24h --database mydb
+
+# Search backups
+dbbackup catalog search --database mydb --start 2024-01-01 --end 2024-12-31
+
+# Get backup info
+dbbackup catalog info 42
+```
+
+## DR Drill Testing
+
+Automated disaster recovery testing restores backups to Docker containers:
+
+```bash
+# Run full DR drill
+dbbackup drill run /backups/mydb_latest.dump.gz \
+  --database mydb \
+  --db-type postgres \
+  --timeout 30m
+
+# Quick drill (restore + basic validation)
+dbbackup drill quick /backups/mydb_latest.dump.gz --database mydb
+
+# List running drill containers
+dbbackup drill list
+
+# Cleanup old drill containers
+dbbackup drill cleanup --age 24h
+
+# Generate drill report
+dbbackup drill report --format html --output drill-report.html
+```
+
+**Drill phases:**
+1. Container creation
+2. Backup download (if cloud)
+3. Restore execution
+4. Database validation
+5. Custom query checks
+6. Cleanup
+
+## Compliance Reports
+
+Generate compliance reports for regulatory frameworks:
+
+```bash
+# Generate SOC2 report
+dbbackup report generate --type soc2 --days 90 --format html --output soc2-report.html
+
+# HIPAA compliance report
+dbbackup report generate --type hipaa --format markdown
+
+# Show compliance summary
+dbbackup report summary --type gdpr --days 30
+
+# List available frameworks
+dbbackup report list
+
+# Show controls for a framework
+dbbackup report controls soc2
+```
+
+**Supported frameworks:**
+- SOC2 Type II (Trust Service Criteria)
+- GDPR (General Data Protection Regulation)
+- HIPAA (Health Insurance Portability and Accountability Act)
+- PCI-DSS (Payment Card Industry Data Security Standard)
+- ISO 27001 (Information Security Management)
+
+## RTO/RPO Analysis
+
+Calculate and monitor Recovery Time/Point Objectives:
+
+```bash
+# Analyze RTO/RPO for a database
+dbbackup rto analyze mydb
+
+# Show status for all databases
+dbbackup rto status
+
+# Check against targets
+dbbackup rto check --rto 4h --rpo 1h
+
+# Set target objectives
+dbbackup rto analyze mydb --target-rto 4h --target-rpo 1h
+```
+
+**Analysis includes:**
+- Current RPO (time since last backup)
+- Estimated RTO (detection + download + restore + validation)
+- RTO breakdown by phase
+- Compliance status
+- Recommendations for improvement
 
 ## Configuration