Add prometheus class

[javidahmed64592]

This pull request introduces a refactor and enhancement of the Prometheus metrics system for the template server. The main change is the extraction of custom metrics logic into a dedicated prometheus_handler.py module, which centralizes metric definitions and operations. This improves maintainability and extensibility, and updates all relevant code and documentation to reflect the new architecture.

Prometheus Metrics Refactor & Enhancement

Metrics System Refactor:

• Added a new python_template_server/prometheus_handler.py module to encapsulate Prometheus metrics setup, metric definitions, and operations, replacing scattered metric logic with a reusable handler class. (prometheus_handler.py is now referenced in docs and .github/copilot-instructions.md) [1] [2] [3]
• Updated python_template_server/template_server.py to use the new PrometheusHandler for all metric operations (incrementing counters, setting gauges) instead of direct metric objects, simplifying and standardizing metric usage. [1] [2] [3] [4] [5] [6]

Metrics Model Improvements:

• Added metric model classes (BaseMetricNames, MetricTypes, MetricConfig) to python_template_server/models.py to define metric names, types, and configuration in a type-safe, extensible way. [1] [2]

Documentation Updates:

• Updated documentation and code listings in .github/copilot-instructions.md and docs/SMG.md to include prometheus_handler.py and describe the new metrics architecture. [1] [2]

These changes make the metrics system easier to maintain, extend, and document, and prepare the codebase for future metric additions and improved observability.