Add auto build binaries for MacOS and Linux

[Mygod]

Fixes #24.

[Copilot]

Pull request overview

This PR adds a GitHub Actions workflow job to automatically build and upload slipstream binaries for macOS ARM64 and Linux x86_64 platforms, addressing issue #24 which requested automated binary builds as artifacts.

Changes:

• Added build-binaries job to the CI workflow with a matrix strategy for macOS ARM64 and Linux x86_64 platforms
• Configured platform-specific dependency installation for both Linux and macOS
• Implemented binary packaging with SHA256 checksum generation
• Set up artifact upload using GitHub Actions artifacts

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[Copilot]

The build commands should include the --features openssl-vendored flag to create portable, self-contained binaries. Without this feature, the binaries will dynamically link against the system's OpenSSL library, which can cause compatibility issues when running on systems with different OpenSSL versions.

The openssl-vendored feature enables static linking of OpenSSL (via openssl-sys's vendored feature), ensuring the binaries work across different Linux distributions and macOS versions without requiring users to have specific OpenSSL versions installed.

This feature is already used in the rust-clippy-features job (line 82) and should be consistently applied to the release binaries as well.

Suggested change

	run: cargo build -p slipstream-client --release --target ${{ matrix.target }}
	- name: Build slipstream-server
	run: cargo build -p slipstream-server --release --target ${{ matrix.target }}
	run: cargo build -p slipstream-client --release --features openssl-vendored --target ${{ matrix.target }}
	- name: Build slipstream-server
	run: cargo build -p slipstream-server --release --features openssl-vendored --target ${{ matrix.target }}