feat: Add Linux ARM64 (aarch64) release artifacts and .deb packages

### Issue Description

**Is your feature request related to a problem? Please describe.**
Currently, pre-built binary releases and `.deb` installation packages are not provided for Linux ARM64 (`aarch64`) architectures. Users running Linux on ARM-based hardware (such as Raspberry Pi 4/5, Apple Silicon Macs via Linux VMs, or AWS Graviton instances) cannot easily install or run Buzz without building from source manually.

**Describe the solution you'd like**
Add Linux ARM64 target support to the automated CI/CD release workflow to build, package, and upload the following artifacts alongside existing releases:

1. Standard Linux ARM64 binary archive (`.tar.gz` or release binary)
2. Linux ARM64 Debian package (`.deb`)

**Describe alternatives you've considered**
Building from source manually on ARM64 devices, which requires setting up the full build environment, dependencies, and compilation toolchains on each local target machine.

**Additional context**

* Expanding build matrix targets to include `linux/arm64` / `aarch64` in GitHub Actions (or equivalent CI pipelines).
* Ensuring `.deb` package creation includes the correct `Architecture: arm64` control metadata.