Setup CI/CD pipeline with GitHub Actions

## Description
Automate the build process for Android APKs and add continuous integration checks using GitHub Actions.

## Proposed Workflows

### 1. Python Tests & Linting
```yaml
# .github/workflows/tests.yml
name: Tests

on: [push, pull_request]

jobs:
test:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- uses: actions/setup-python@v4
with:
python-version: '3.x'
- run: pip install -r requirements.txt pytest flake8
- run: flake8 main.py
- run: pytest
```

### 2. Android APK Build
```yaml
# .github/workflows/android-build.yml
name: Build APK

on:
push:
tags:
- 'v*'

jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- name: Build with Buildozer
uses: ArtemSBulgakov/buildozer-action@v1
with:
command: buildozer android debug
- name: Upload APK
uses: actions/upload-artifact@v3
with:
name: package
path: bin/*.apk
```

## Benefits
- Automated testing on every push
- Automatic APK builds on version tags
- Code quality checks
- Faster release process

## Additional Setup
- Add `requirements.txt` file
- Configure Buildozer for CI environment
- Setup GitHub Releases automation

Start by reviewing main.py, requirements.txt, and the proposed .github/workflows/tests.yml and .github/workflows/android-build.yml entry points, along with the repository's Buildozer configuration. Confirm the Python test and lint commands and the Android build prerequisites. Done means checks run on pushes and pull requests, tagged builds produce an APK artifact, and the release setup is documented or automated as requested.

Written by the indexing model from the issue text.