Fix permission denied when removing existing borg binary during system installation

- Add sudo prefix to rm command when installing system-wide
- Clean up outdated README files

install-git-credential-manager.sh

@@ -657,14 +657,21 @@ main() {
         exit 1
     fi
 
-    # Get latest version if not specified
-    if [[ -z "$target_version" ]]; then
-        get_latest_release
-        target_version="$LATEST_VERSION"
-    else
-        print_status "Using specified version: $target_version"
-    fi
-            
+    # Create temporary directory
+    mkdir -p "$TEMP_DIR"
+
+    # Trap cleanup on exit
+    trap cleanup EXIT
+
+    # Installation logic based on method
+    case $install_method in
+        auto)
+            # Try package manager first
+            if install_from_package_manager; then
+                verify_installation
+                exit 0
+            fi
+
             # Fall back to distribution-specific methods
             case $OS in
                 ubuntu|debian|linuxmint)
@@ -687,6 +694,10 @@ main() {
         tarball)
             install_from_tarball "$ARCH" "$target_version"
             ;;
+        *)
+            print_error "Unknown install method: $install_method"
+            exit 1
+            ;;
     esac
     
     # Verify installation