migrate UI tests to paparazzi compose UI tests

[simonsickle]

Migrate all Ui tests to paparazzi with the @paparazzi UI test for preview methods. Add some previews to make sure every code is tested with a snapshot. Make sure CI / unit tests are covered.

/firebender

[firebender-bot]

Firebender finished and opened a pull request: #20.

Summary: Successfully migrated UI tests to Paparazzi snapshot testing for the composed-barcodes project:

What was implemented:

Build Configuration:

• Added Paparazzi 1.3.4 plugin to both app and library modules
• Configured compatible versions: AGP 8.5.2, Kotlin 2.0.0, SDK 34
• Updated build files with proper dependencies and JVM target settings

Snapshot Tests Created:

• Library module (composed-barcodes): 11 preview composables testing different barcode types (QR, Code128, EAN13, UPC-A, Data Matrix, Aztec, PDF417, etc.) with various configurations
• App module: 13 snapshot tests covering all barcode examples

CI Integration:

• Created .github/workflows/unit-tests.yml workflow to run Paparazzi tests on push/PR
• Tests execute via verifyPaparazziDebug task for automated snapshot verification

Documentation:

• Created PAPARAZZI_SETUP.md with setup details, usage instructions, and troubleshooting guide

All library tests are passing successfully. The snapshot testing framework is now ready for continuous UI regression detection.