ARM architecture plan

**Is your feature request related to a problem? Please describe.**

eic-shell currently runs only through AMD64/x86_64 container images. On Apple Silicon systems (ARM64/aarch64), this requires emulation (Rosetta/QEMU), which significantly reduces performance during CPU-intensive workflows such as npsim and especially eicrecon.

For large-scale reconstruction campaigns with background mixing enabled, the slowdown becomes substantial and limits usability on modern ARM64 laptops and workstations.

I understand that much of the HEP and detector simulation ecosystem has historically targeted AMD64/x86_64 platforms, and that some dependencies may still be architecture-specific. However, it may already be possible to support at least part of the software stack natively on ARM64.

**Describe the solution you'd like**

Provide native ARM64/aarch64 support for eic-shell, including:
- ARM64 container images
- multi-architecture Docker builds (linux/amd64 and linux/arm64)
- CI validation on Apple Silicon and/or ARM64 Linux
- documentation for ARM-native installation and execution

Ideally, users on Apple Silicon Macs should be able to run eic-shell natively without requiring x86 emulation.

Even partial ARM64 compatibility for selected components would already be very valuable.

**Describe alternatives you've considered**

Current alternatives include:
- running through Rosetta/QEMU emulation on macOS
- using remote x86_64 servers or clusters
- manually rebuilding dependencies for ARM64

However, these approaches either introduce large performance penalties or significantly increase setup complexity.

**Additional context**

On Apple Silicon systems, workflows involving:
- background overlay,
- npsim,
- and especially eicrecon

can become substantially slower under x86 emulation.

Native ARM64 support would improve:
- developer experience,
- portability,
- battery efficiency,
- and local reconstruction performance for EIC software users on modern hardware platforms.