Add unit tests for Flask application, static files, and timer service

[j-sk100]

This pull request introduces the initial implementation of a Pomodoro timer web application with a Flask backend and a modern HTML/CSS/JavaScript frontend. It establishes the foundational architecture, main features, service layer, and testing infrastructure for the app. The most important changes are grouped below.

Backend Implementation and API Endpoints:

• Added app.py with Flask routes for main UI, history management, statistics, and timer settings validation APIs, using the service layer for business logic.
• Implemented services/timer_service.py containing HistoryService and TimerService classes for history management, statistics calculation, and timer settings validation.
• Added services/__init__.py to initialize the service layer package.

Frontend and UI:

• Created templates/index.html with a structured Pomodoro timer UI, including timer display, controls, settings panel, history/statistics section, and integration with static CSS/JS.

Architecture, Feature Planning, and Testing:

• Added architecture.md, features.md, and plan.md documents to outline app structure, feature set, and stepwise implementation plan. [1] [2] [3]
• Added unit test for the Flask app in tests/test_app.py, verifying routes, static files, and page elements.
• Added pyproject.toml for pytest and coverage configuration, and run_tests.sh for test execution and coverage reporting. [1] [2]
• Initialized test and service packages with tests/__init__.py and services/__init__.py. [1] [2]

Development Environment:

• Added .vscode/mcp.json for local MCP server configuration.

These changes lay the groundwork for a maintainable, testable, and extensible Pomodoro timer web application.[Copilot is generating a summary...]- Implemented unit tests for the main Flask application, ensuring routes, static files, and HTML structure are correctly set up.

• Created tests for the existence and structure of JavaScript and CSS files.
• Developed comprehensive tests for the timer service, including history management and timer settings validation.
• Ensured all tests cover edge cases and validate expected behaviors for various functionalities.