Add cargo check step to Rust CI workflow

[tascord]

Added a step to run cargo check with warnings as errors.

[Copilot]

Pull Request Overview

This PR adds a GitHub Actions CI workflow for Rust projects that includes cargo check with warnings treated as errors before building.

• Introduces a new Rust CI workflow that runs on pushes and pull requests to main branch
• Adds cargo check step with warnings as errors to catch potential issues early
• Includes standard cargo build step with verbose output

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[Copilot]

Consider using RUSTFLAGS environment variable instead of CARGO_BUILD_RUSTFLAGS for broader compatibility. RUSTFLAGS is the standard way to pass flags to rustc and works consistently across different cargo commands.

Suggested change

	run: CARGO_BUILD_RUSTFLAGS='-D warnings' cargo check --verbose
	run: RUSTFLAGS='-D warnings' cargo check --verbose

[Copilot]

The build step should also use the same RUSTFLAGS='-D warnings' to ensure consistency between check and build phases. This prevents warnings from being introduced that pass check but would fail in a production build with warnings as errors.

Suggested change

	run: cargo build --verbose
	run: CARGO_BUILD_RUSTFLAGS='-D warnings' cargo build --verbose