Add performance metrics for notification detail fetching

[senomorf]

Observability Enhancement: Performance Metrics

Issue Description

The notification system currently lacks visibility into performance metrics for instance detail fetching, making it difficult to:

• Monitor API response times and detect degradation
• Track notification latency for user experience analysis
• Identify performance bottlenecks in the notification pipeline
• Measure impact of parallel processing optimizations

Current State

No timing or performance metrics are captured during the notification detail fetching process.

Business Impact

• Limited operational visibility into notification performance
• Difficulty troubleshooting slow notification scenarios
• No data to validate performance improvements
• Missing insights for capacity planning and optimization

Recommended Implementation

Add timing metrics throughout the notification detail fetching process:

# Add performance metric tracking to get_instance_details()
get_instance_details() {
    local instance_id="$1"
    local shape_name="$2"
    local detail_start_time
    detail_start_time=$(date +%s)
    
    # ... existing implementation ...
    
    # Record performance metrics
    local detail_duration=$(($(date +%s) - detail_start_time))
    local success_indicator
    
    if [[ -n "$id" && "$id" != "unknown" ]]; then
        success_indicator="success"
    else
        success_indicator="failure"
    fi
    
    log_performance_metric "NOTIFICATION_DETAILS" "fetch" "$detail_duration" "$success_indicator"
}

# Add timing for overall notification process
send_notification_with_details() {
    local notification_start_time
    notification_start_time=$(date +%s)
    local success_count=0
    
    # ... process both instances ...
    
    local total_duration=$(($(date +%s) - notification_start_time))
    log_performance_metric "NOTIFICATION_TOTAL" "process" "$total_duration" "$success_count"
}

Metrics to Track

1. Instance Detail Fetch Duration per shape (A1/E2)
2. Total Notification Processing Time end-to-end
3. API Call Success Rate for instance details
4. VNIC Data Retrieval Time for IP address fetching
5. Notification Assembly Time for message formatting

Output Format

# Example performance log entries
[PERF] NOTIFICATION_DETAILS fetch A1.Flex duration=3s status=success
[PERF] NOTIFICATION_DETAILS fetch E2.1.Micro duration=2s status=success  
[PERF] NOTIFICATION_TOTAL process duration=8s instances=2
[PERF] VNIC_FETCH get vnic_id=ocid1.vnic... duration=1s status=success

Benefits

• Performance monitoring for notification system health
• Optimization validation when implementing parallel processing
• Troubleshooting data for slow notification scenarios
• Capacity planning insights for API usage patterns
• User experience metrics for notification responsiveness

Integration Points

• GitHub Actions logs for workflow performance analysis
• Log aggregation systems for historical trend analysis
• Alerting systems for performance degradation detection
• Dashboard creation for operational visibility

Priority

Low - Observability enhancement that supports long-term optimization.

Context

Identified in PR #89 code review by Claude Code automated review system.

Acceptance Criteria

• Add timing metrics for instance detail fetching per shape
• Track total notification processing duration end-to-end
• Implement performance logging function with consistent format
• Include success/failure indicators in metrics
• Add VNIC data retrieval timing measurements
• Test metrics collection with various notification scenarios
• Validate metric accuracy with manual timing verification
• Ensure metrics don't impact notification performance significantly