Use functions to wrap package managers and detect if the aikido commands are available

src/shell-integration/startup-scripts/init-fish.fish

@@ -0,0 +1,85 @@
+function installIfCommandNotFound
+    set cmd $argv[1]
+    
+    # Check if the command already exists
+    if type -q $cmd
+        return 0
+    end
+    
+    # Check if Node.js version is below 18
+    # Safe-chain requires Node.js 18 or higher
+    set node_version (node -v | sed 's/v//' | cut -d'.' -f1)
+    if test $node_version -lt 18
+        return 2
+    end
+    
+    # Command not found, ask user if they want to install safe-chain
+    read -l response -P "The command '$cmd' is not available. Do you want to install safe-chain to provide it? (y/N): "
+    
+    if string match -qi 'y*' $response
+        printf "Installing safe-chain...\n"
+        installSafeChain
+        
+        if test $status -ne 0
+            printf "\nFailed to install safe-chain. Exiting.\n"
+            return 1
+        end
+        
+        return 0
+    else
+        printf "Skipping safe-chain installation. Using original command instead.\n"
+        return 2
+    end
+end
+
+function installSafeChain
+    command npm install -g @aikidosec/safe-chain
+    
+    if test $status -ne 0
+        return 1
+    end
+
+    printf "------\n"
+end
+
+function wrapCommand
+    set original_cmd $argv[1]
+    set aikido_cmd $argv[2]
+    set cmd_args $argv[3..-1]
+    
+    installIfCommandNotFound $aikido_cmd
+    set install_result $status
+    
+    if test $install_result -eq 2
+        command $original_cmd $cmd_args
+    else
+        $aikido_cmd $cmd_args
+    end
+end
+
+function npx
+    wrapCommand "npx" "aikido-npx" $argv
+end
+
+function yarn
+    wrapCommand "yarn" "aikido-yarn" $argv
+end
+
+function pnpm
+    wrapCommand "pnpm" "aikido-pnpm" $argv
+end
+
+function pnpx
+    wrapCommand "pnpx" "aikido-pnpx" $argv
+end
+
+function npm
+    if test (count $argv) -eq 1 -a \( "$argv[1]" = "-v" -o "$argv[1]" = "--version" \)
+        # If args is just -v or --version and nothing else, just run the npm version command
+        # This is because nvm uses this to check the version of npm
+        command npm $argv
+        return
+    end
+
+    wrapCommand "npm" "aikido-npm" $argv
+end