chore: added initial tests for the component

[troinine]

No description provided.

[Copilot]

Pull request overview

This PR adds initial test coverage for the weather forecast card component using Vitest and happy-dom. The tests validate rendering behavior, user interactions (like toggling between daily and hourly forecasts), and data display across different forecast modes.

• Configures Vitest with happy-dom environment and custom plugin for handling Parcel bundle-text imports
• Adds comprehensive tests for simple forecast, chart forecast, and general card functionality
• Reduces mock subscription timeout from 1000ms to 100ms to improve test execution speed

Reviewed changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
vitest.config.ts	Configures Vitest with happy-dom and custom plugin for Parcel compatibility
test/weather-forecast-simple.test.ts	Tests simple forecast mode rendering and interactions
test/weather-forecast-chart.test.ts	Tests chart forecast mode with canvas rendering and data validation
test/weather-forecast-card.test.ts	Tests core card functionality including temperature and condition display
test/vitest.setup.ts	Suppresses console output during tests
test/mocks/test-data.ts	Adds test fixture data for daily and hourly forecasts
test/mocks/hass.ts	Reduces subscription callback timeout for faster test execution
src/components/wfc-weather-condition-icon-provider.ts	Adds data-condition attribute to support test assertions
package.json	Adds test scripts and dependencies (vitest, happy-dom, @open-wc/testing)
.github/workflows/build.yml	Integrates test execution into CI workflow

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