…lized in helper methods

- SdkConfigPanel: headerLabel, statusLabel
- AvdGridPanel: pageLabel, prevPageButton, nextPageButton
- LogPanel: logLabel, clearButton

These fields were causing compilation errors because they were marked final
but assigned in createXXX() methods instead of directly in constructor.
Removed unnecessary workaround in AvdGridPanel constructor.

- Set background colors explicitly using UIManager.getColor()
- Replace hardcoded Color.GRAY with theme-aware colors
- Add alpha channel for dimmed secondary text
- Fix all panels (cards, topPanel, infoPanel, actionsPanel, bottomPanel)
- Fix placeholder panels border color
- All labels now use Label.foreground color

Fixes white-on-white text issue in dark mode.

This is the real fix for dark mode support. The issue was that UI components
were being created before UIManager.setLookAndFeel() was called, causing them
to use default Metal L&F colors instead of system theme colors.

Changes:
- Move setLookAndFeel() from initializeUI() to constructor, before creating components
- Remove 'final' from component fields (now initialized in constructor)
- Revert all explicit setBackground() calls - unnecessary with correct L&F initialization
- Restore original simple code for panels, labels, and placeholders

The key insight: In Swing, Look and Feel must be set BEFORE instantiating any
UI components, otherwise they won't inherit the system theme colors.

Added 55 unit tests across 5 test classes to ensure code quality
and prevent regressions after the MVC refactoring.

Test coverage:
- AndroidVersionMapperTest: 19 tests
  * API level to version name mapping
  * Config file parsing
  * Target string parsing
  * Edge cases and null handling

- DeviceNameFormatterTest: 21 tests
  * Device name formatting (underscore to space)
  * AVD name validation
  * Special characters rejection
  * Edge cases (null, empty, whitespace)

- ThemeUtilsTest: 11 tests
  * Color constants verification
  * Material Design compliance
  * Theme detection methods
  * Utility class instantiation prevention

- EmulatorStatusTest: 8 tests
  * Enum values verification
  * valueOf and ordinal tests
  * Switch statement compatibility

- MainControllerTest: 3 tests
  * Smoke tests for instantiation
  * Headless mode handling
  * View initialization verification

All tests use JUnit 5 and follow AAA pattern (Arrange-Act-Assert).
Tests are designed to run in both GUI and headless environments.

Implemented comprehensive code quality infrastructure with automated
testing, coverage reporting, and quality badges.

Changes:
1. pom.xml:
   - Added JaCoCo plugin (v0.8.11) for code coverage
   - Configured coverage minimum threshold (50%)
   - Automatic report generation on test phase

2. GitHub Actions (.github/workflows/code-quality.yml):
   - New workflow for code quality checks
   - Three jobs: test-and-coverage, code-analysis, build-quality
   - Automated coverage upload to Codecov
   - PR comments with coverage reports
   - Artifact archiving for reports and builds

3. Codecov configuration (codecov.yml):
   - Project coverage target: 50%
   - Patch coverage target: 60%
   - Automatic PR comments with coverage diff
   - Ignore test files from coverage calculation

4. README.md:
   - Added Code Quality workflow badge
   - Added Codecov coverage badge
   - Updated CI/CD section with quality checks info
   - Mentioned 55 unit tests in features

Features:
✅ Automated test execution on push/PR
✅ Code coverage reporting with JaCoCo
✅ Codecov integration for visual coverage tracking
✅ PR comments with coverage delta
✅ Coverage badges in README
✅ Artifact archiving (reports + JAR)
✅ Multi-job pipeline (test → analyze → build)

Benefits:
- Prevents regressions with automated testing
- Enforces minimum 50% code coverage
- Visual feedback on PRs with coverage reports
- Historical coverage tracking via Codecov
- Professional quality badges for repository

Note: Codecov token needs to be added to GitHub secrets as CODECOV_TOKEN

Added @NoArgsConstructor and @AllArgsConstructor Lombok annotations to:
- SdkConfiguration
- DeviceConfiguration

This fixes compilation errors in tests that use no-args constructors
while maintaining builder and all-args constructor functionality.