feat: Integrate Spotless for code formatting and update license

This commit introduces Spotless for automated code formatting and updates the project license from MIT to Apache License 2.0. It also adds copyright headers to all relevant files and includes new GitHub action files for funding and code owners.

Key changes:
- Updated `LICENSE` file from MIT to Apache License 2.0.
- Added copyright headers to all `.kt`, `.kts`, and `.xml` files.
- Added `spotless` plugin to `build.gradle.kts` (root and app module) and `libs.versions.toml`.
- Configured Spotless in `app/build.gradle.kts` to format Kotlin, KTS, and XML files using new copyright header files in the `spotless/` directory.
- Created `spotless/copyright.kt`, `spotless/copyright.kts`, and `spotless/copyright.xml` for license headers.
- Added `.github/FUNDING.yaml` to specify funding options.
- Added `.github/CODEOWNERS` to define code ownership.
- Updated `README.md` to reflect the license change.