feat: Add issue templates and update README

This commit introduces GitHub issue templates for bug reports and feature requests, and a pull request template to streamline contributions. It also updates the README.md with more detailed information about the project's features, tech stack, and usage, emphasizing the use of an alpha version of Jetpack Compose for Material 3 expressive features.

Key changes:
- Added `.github/bug_report.md` for standardized bug reporting.
- Added `.github/feature_request.md` for structured feature suggestions.
- Added `.github/PULL_REQUEST_TEMPLATE.md` to guide pull request submissions.
- Updated `README.md` to:
    - Highlight the minimal setup and the use of Jetpack Compose alpha for Material 3 expressive features.
    - Provide more detail on the tech stack, including specific mentions of the alpha Compose version.
    - Clarify prerequisites, recommending the latest Canary version of Android Studio for alpha Compose compatibility.
    - Refine the project structure overview.
    - Expand on project usage, including rapid prototyping and as a learning resource.
- Added `.idea/git_toolbox_prj.xml` to configure GitToolBox plugin settings for commit message validation.