feat(install): improve Arduino CLI installation and add ca-certificates dependency

- Replace shell script installation with direct download approach for better reliability
- Use GitHub API to get latest Arduino CLI version automatically
- Add proper cleanup of temporary files after installation
- Include ca-certificates package in Arch Linux base packages for secure connections
- Maintain backward compatibility with existing installation flow

lib/packages.sh

@@ -5,7 +5,7 @@ step "1/9 — Installing base packages"
 
 if $IS_ARCH; then
   sudo pacman -Syu --noconfirm
-  $PKG_INSTALL base-devel git curl unzip wget ripgrep fd bat eza tree jq zsh clang
+  $PKG_INSTALL base-devel git curl unzip wget ripgrep fd bat eza tree jq zsh clang ca-certificates
   # tio is in AUR — install yay if needed, then tio
   if ! command -v yay &>/dev/null; then
     info "Installing yay (AUR helper)..."
@@ -16,7 +16,7 @@ if $IS_ARCH; then
   yay -S --needed --noconfirm tio
 else
   sudo apt update && sudo apt upgrade -y
-  $PKG_INSTALL build-essential git curl unzip wget ripgrep bat eza tree jq zsh clang-format tio
+  $PKG_INSTALL build-essential git curl unzip wget ripgrep bat eza tree jq zsh clang-format tio ca-certificates
   # fd is named differently on Ubuntu
   sudo apt install -y fd-find 2>/dev/null || true
 fi