[Enhancement] Expose Prometheus-compatible metrics across all services

[vraj826]

📌 Description

This PR introduces Prometheus-compatible observability across the entire MicroForge microservices ecosystem, enabling unified monitoring, metrics scraping, and future Grafana integration.

All core services now expose a standardized /metrics endpoint following Prometheus best practices, ensuring production-ready observability in both Docker Compose and Kubernetes environments.

🔹 Auth Service (Go + Gin)

• Integrated prometheus/client_golang
• Added request-level metrics via middleware
• Exposed /metrics endpoint
• Tracks HTTP request count and latency

🔹 Login Service (Spring Boot)

• Enabled Micrometer Prometheus registry
• Configured Spring Boot Actuator Prometheus endpoint
• Metrics available at /actuator/prometheus

🔹 Metadata Service (Flask)

• Integrated prometheus-client
• Exposed /metrics endpoint
• Default Python runtime + GC metrics available
• Compatible with Prometheus scraping

🔹 Notification Service (Node.js + Express)

• Integrated prom-client
• Added request-count middleware
• Exposed /metrics endpoint
• Collects Node.js runtime and HTTP metrics

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🔗 Related Issue

Fixes #50

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🛠️ Type of Change

Please mark the relevant option:

• Documentation update
• Bug fix
• ✅ New feature
• Refactor
• ✅ Configuration / DevOps change
• Other (please explain)

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🧪 How Was This Tested?

Describe how you verified your changes:

• Docker Compose runs successfully
• Frontend loads correctly
• ✅ Service builds without errors
• Documentation renders correctly
• ✅ Manual testing

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✅ Checklist

Please confirm the following:

• ✅ My code follows the project structure
• ✅ I tested my changes locally
• ✅ I linked the relevant issue
• ✅ I kept this PR focused and minimal
• ✅ I am open to feedback and changes

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[github-actions]

🚫 Pull Request Policy Violation

Hi @vraj826, thanks for your contribution!

Direct PRs to the master branch are not allowed. Please close this PR and target the stage branch instead for review.