fix: auto-remove CD-ROM apt source when internet sources are available

On minimal Ubuntu installs, the CD-ROM source persists in sources.list
and breaks apt-get update. Now detect and remove it before installing
git, and verify git is actually available after installation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

linux-managements/setup.sh

@@ -184,13 +184,45 @@ install_git() {
         success "git already installed ($(git --version))"
         return
     fi
+    # On some Ubuntu installs the CD-ROM source is still present and breaks
+    # apt-get update once the machine has internet sources configured.
+    # Remove it automatically so the rest of the script can proceed.
+    clean_cdrom_sources() {
+        # Traditional sources.list format
+        if grep -qE '^\s*deb\s.*cdrom:' /etc/apt/sources.list 2>/dev/null; then
+            has_internet=false
+            if grep -E '^\s*deb\s' /etc/apt/sources.list 2>/dev/null | grep -qv 'cdrom:'; then
+                has_internet=true
+            elif grep -rE '^\s*deb\s' /etc/apt/sources.list.d/ 2>/dev/null | grep -qv 'cdrom:'; then
+                has_internet=true
+            fi
+            if [ "$has_internet" = true ]; then
+                info "Removing CD-ROM apt source (internet sources detected)"
+                psudo sed -i '/cdrom:/d' /etc/apt/sources.list
+            fi
+        fi
+        # DEB822 format (.sources files)
+        for f in /etc/apt/sources.list.d/*.sources; do
+            [ -f "$f" ] || continue
+            if grep -qE '^\s*URIs:\s*.*cdrom:' "$f" 2>/dev/null; then
+                info "Removing CD-ROM apt source from $(basename "$f")"
+                psudo sed -i '/URIs:.*cdrom:/d' "$f"
+            fi
+        done
+    }
+
     info "Installing git via system package manager ..."
     case "$DISTRO" in
         aosc)           psudo oma install -y git ;;
-        debian|ubuntu)  psudo apt-get update -qq && psudo apt-get install -y git ;;
+        debian|ubuntu)  clean_cdrom_sources; psudo apt-get update -qq; psudo apt-get install -y git ;;
         fedora)         psudo dnf install -y git ;;
     esac
-    success "git installed"
+    if command -v git &>/dev/null; then
+        success "git installed ($(git --version))"
+    else
+        error "git installation failed"
+        exit 1
+    fi
 }
 
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