Add Tauri to community gitignore templates

[mvanhorn]

Reasons for making this change

Tauri is a cross-platform desktop application framework (90k+ GitHub stars) that combines a web frontend with a Rust backend. Tauri projects produce platform-specific build artifacts - MSI installers, DMGs, AppImages, deb packages - that should not be committed.

The template covers two Tauri-specific patterns not in the existing Rust.gitignore:

• target/ - Rust Cargo build cache, present in all Tauri projects
• WixTools/ - WiX Toolset cache directory created during Windows MSI installer builds

The header recommends combining with Rust.gitignore for generic Rust patterns.

Intentionally NOT ignored:

• src-tauri/gen/ - Contains generated Android Studio and Xcode project files. Tauri's own community discussion confirms these should be committed since they may need customization.

Placement: community/ per the repo's README guidelines for specialized framework templates.

Links to documentation supporting these rule changes

• Tauri's own .gitignore ignores target/ and example gen/ directories
• Tauri example src-tauri/.gitignore ignores target/ and WixTools
• Tauri Windows Installer docs documents the WiX Toolset and its local cache
• Tauri discussion #8323 discusses why gen/ should be committed

If this is a new template

Link to application or project's homepage: https://tauri.app/

Merge and Approval Steps

• Confirm that you've read the contribution guidelines and ensured your PR aligns
• Ensure CI is passing
• Get a review and Approval from one of the maintainers

This contribution was developed with AI assistance (Claude Code).