Refactor loading of configuration

[zaro0508]

Use the AWS CDK built in context loader[1] and allow storing and loading configurations from files.

[1] https://docs.aws.amazon.com/cdk/v2/guide/context.html

depends on #25

[Copilot]

Pull Request Overview

This PR refactors configuration loading to use AWS CDK's built-in context mechanism and file-based configuration. Configuration is moved from hardcoded environment variables in Python to YAML files, enabling better separation of concerns and leveraging CDK's standard context loading pattern.

Key Changes:

• Replaces inline environment variable dictionary with file-based configuration system
• Adds load_context_config() utility function supporting YAML/JSON files with base config merging
• Updates CDK context from environment variable (ENV) to CDK context parameter (--context env=<env>)

Reviewed Changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/utils.py	Implements new configuration loader with validation and file format support
tests/unit/test_utils.py	Comprehensive test suite for configuration loading functionality
config/*.yaml	Environment-specific configuration files for dev, stage, prod, and base
app.py	Refactored to use file-based config instead of inline dictionaries
tests/unit/test_network_stack.py	Updated to load config from files
tests/unit/test_service_stack.py	Updated to load config from files
README.md	Updated documentation for new configuration approach
.github/workflows/*.yaml	Updated workflows to use CDK context parameter

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[Copilot]

Pull Request Overview

Copilot reviewed 12 out of 13 changed files in this pull request and generated 2 comments.

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[ConsoleCatzirl]

This generally looks good, but there's one test that looks like a duplicate of another test (not a big deal).