Add remaining elements for create kernel app (#48)

This PR competes the remaining work for
[KERNEL-374](https://linear.app/onkernel/issue/KERNEL-374/port-create-kernel-app-to-the-kernel-cli)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Implements the `kernel create` flow with template selection and
overwrite prompts, adds deploy/invoke guidance per template, expands
tests, and updates README docs.
> 
> - **Create CLI**:
> - Implement `kernel create` with `create.CreateInput` type,
interactive prompts, and overwrite confirmation via
`PromptForOverwrite`.
> - Copies template files with spinner feedback; handles existing dirs
by optional removal.
> - Refactor install flow: `InstallDependencies(appPath, CreateInput)`;
prints tailored next steps on failure/missing tools.
> - **Templates & Commands**:
> - Add template key constants and `Templates` map; provide
`GetDeployCommand` and `GetInvokeSample` via new `Commands` matrix per
language/template.
> - Normalize language shorthands; expose supported templates per
language.
> - **Tests**:
> - Major expansion: creation flow, dependency failure/missing tool
paths, overwrite behavior, permissions, invalid combos, shorthands, and
template coverage (`pkg/create/copy_test.go`, updates to
`cmd/create_test.go`).
> - **Docs**:
> - README: add app creation to capabilities, reorder Quick Start
(create → login → deploy → invoke), document create flags/templates, and
add create examples.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
83f218a. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: archandatta

README.md

@@ -21,6 +21,7 @@ Kernel provides sandboxed, ready-to-use Chrome browsers for browser automations
 
 ### What you can do with the CLI
 
+- Create new Kernel applications from templates
 - Deploy and version apps to Kernel
 - Invoke app actions (sync or async) and stream logs
 - Create, list, view, and delete managed browser sessions
@@ -50,19 +51,25 @@ kernel --version
 
 ## Quick Start
 
-1. **Authenticate with Kernel:**
+1. **Create a new Kernel app:**
+
+   ```bash
+   kernel create
+   ```
+
+2. **Authenticate with Kernel:**
 
    ```bash
    kernel login
    ```
 
-2. **Deploy your first app:**
+3. **Deploy your app:**
 
    ```bash
    kernel deploy index.ts
    ```
 
-3. **Invoke your app:**
+4. **Invoke your app:**
    ```bash
    kernel invoke my-app action-name --payload '{"key": "value"}'
    ```
@@ -103,6 +110,20 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 - `kernel logout` - Clear stored credentials
 - `kernel auth` - Check authentication status
 
+### App Creation
+
+- `--name <name>`, `-n` - Name of the application
+- `--language <language>`, `-l` - Sepecify app language: `typescript`, or `python`
+- `--template <template>`, `-t` - Template to use:
+  - `sample-app` - Basic template with Playwright integration
+  - `advanced-sample` - Sample apps using advanced Kernel configs
+  - `stagehand` - Template with Stagehand SDK (TypeScript only)
+  - `browser-use` - Template with Browser Use SDK (Python only)
+  - `computer-use` - Anthropic Computer Use prompt loop
+  - `cua` - OpenAI Computer Using Agent (CUA) sample
+  - `gemini-cua` - Google Gemini CUA sample (TypeScript only)
+  - `magnitude` - Magnitude framework sample (TypeScript only)
+
 ### App Deployment
 
 - `kernel deploy <file>` - Deploy an app to Kernel
@@ -356,6 +377,25 @@ Create an API key from the [Kernel dashboard](https://dashboard.onkernel.com).
 
 ## Examples
 
+### Create a new app
+
+```bash
+# Interactive mode (prompts for all options)
+kernel create
+
+# Create a TypeScript app with sample template
+kernel create --name my-app --language typescript --template sample-app
+
+# Create a Python app with Browser Use
+kernel create --name my-scraper --language python --template browser-use
+
+# Create a TypeScript app with Stagehand
+kernel create --name my-agent --language ts --template stagehand
+
+# Create a Python Computer Use app
+kernel create --name my-cu-app --language py --template computer-use
+```
+
 ### Deploy with environment variables
 
 ```bash

cmd/create.go

@@ -11,26 +11,32 @@ import (
 	"github.com/spf13/cobra"
 )
 
-type CreateInput struct {
-	Name     string
-	Language string
-	Template string
-}
-
 // CreateCmd is a cobra-independent command handler for create operations
 type CreateCmd struct{}
 
 // Create executes the creating a new Kernel app logic
-func (c CreateCmd) Create(ctx context.Context, ci CreateInput) error {
+func (c CreateCmd) Create(ctx context.Context, ci create.CreateInput) error {
 	appPath, err := filepath.Abs(ci.Name)
 	if err != nil {
 		return fmt.Errorf("failed to resolve app path: %w", err)
 	}
 
-	// TODO: handle overwrite gracefully (prompt user)
-	// Check if directory already exists
+	// Check if directory already exists and prompt for overwrite
 	if _, err := os.Stat(appPath); err == nil {
-		return fmt.Errorf("directory %s already exists", ci.Name)
+		overwrite, err := create.PromptForOverwrite(ci.Name)
+		if err != nil {
+			return fmt.Errorf("failed to prompt for overwrite: %w", err)
+		}
+
+		if !overwrite {
+			pterm.Warning.Println("Operation cancelled.")
+			return nil
+		}
+
+		// Remove existing directory
+		if err := os.RemoveAll(appPath); err != nil {
+			return fmt.Errorf("failed to remove existing directory: %w", err)
+		}
 	}
 
 	if err := os.MkdirAll(appPath, 0755); err != nil {
@@ -45,8 +51,9 @@ func (c CreateCmd) Create(ctx context.Context, ci CreateInput) error {
 		spinner.Fail("Failed to copy template files")
 		return fmt.Errorf("failed to copy template files: %w", err)
 	}
+	spinner.Success()
 
-	nextSteps, err := create.InstallDependencies(ci.Name, appPath, ci.Language)
+	nextSteps, err := create.InstallDependencies(appPath, ci)
 	if err != nil {
 		return fmt.Errorf("failed to install dependencies: %w", err)
 	}
@@ -91,7 +98,7 @@ func runCreateApp(cmd *cobra.Command, args []string) error {
 	}
 
 	c := CreateCmd{}
-	return c.Create(cmd.Context(), CreateInput{
+	return c.Create(cmd.Context(), create.CreateInput{
 		Name:     appName,
 		Language: language,
 		Template: template,