Feat: Add Arch / Manjaro Linux support to setup.sh #1381

Describe the feature

Currently, the automated setup script (scripts/setup.sh) only includes package installation branches for:

• Debian-based distributions (using apt)
• Fedora/RedHat-based distributions (using dnf)

If a developer runs this script on Arch Linux or Arch-based distributions (such as Manjaro, Mabox Linux, or EndeavourOS), the script exits immediately with:
Unsupported OS: Linux. Please install system dependencies manually.

Proposed Enhancement

I would like to add a branch for Arch-based distributions to detect pacman and automatically install the required system libraries and packages:

• webkit2gtk-4.1 (Tauri WebView engine)
• base-devel (Build essential development tools)
• curl
• wget
• file
• xdotool (Contains libxdo headers/libs)
• openssl
• libayatana-appindicator (System indicator applets)
• librsvg (SVG rendering library)
• nodejs & npm (In Arch Linux, npm is a separate package from nodejs, so both need to be installed explicitly)
• rustup (To configure the Rust stable toolchain)
• pyenv (To compile and manage Python versions locally)

This will ensure a smoother onboarding experience for developers developing on Arch-based systems.

Add ScreenShots

N/A (CLI setup script error)

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