feat: add early v4 detection for improved update flow

- Now detects existing v4 installations immediately after directory prompt
- Offers update option upfront for existing v4 installations
- If user declines update, continues with normal installation flow
- Added 'update' install type handling in installer
- Improves user experience by streamlining the update process

🤖 Generated with [Claude Code](https://claude.ai/code)

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

tools/installer/bin/bmad.js

@@ -1,6 +1,7 @@
 #!/usr/bin/env node
 
 const { program } = require('commander');
+const path = require('path');
 
 // Dynamic imports for ES modules
 let chalk, inquirer;
@@ -158,6 +159,33 @@ async function promptInstallation() {
   ]);
   answers.directory = directory;
 
+  // Check if this is an existing v4 installation
+  const installDir = path.resolve(answers.directory);
+  const state = await installer.detectInstallationState(installDir);
+  
+  if (state.type === 'v4_existing') {
+    console.log(chalk.yellow('\n🔍 Found existing BMAD v4 installation'));
+    console.log(`   Directory: ${installDir}`);
+    console.log(`   Version: ${state.manifest?.version || 'Unknown'}`);
+    console.log(`   Installed: ${state.manifest?.installed_at ? new Date(state.manifest.installed_at).toLocaleDateString() : 'Unknown'}`);
+    
+    const { shouldUpdate } = await inquirer.prompt([
+      {
+        type: 'confirm',
+        name: 'shouldUpdate',
+        message: 'Would you like to update your existing BMAD v4 installation?',
+        default: true
+      }
+    ]);
+    
+    if (shouldUpdate) {
+      // Skip other prompts and go directly to update
+      answers.installType = 'update';
+      return await installer.install(answers);
+    }
+    // If user doesn't want to update, continue with normal flow
+  }
+
   // Ask for installation type
   const { installType } = await inquirer.prompt([
     {

tools/installer/lib/installer.js

@@ -102,6 +102,17 @@ class Installer {
         spinner.start("Analyzing installation directory...");
       }
 
+      // If this is an update request from early detection, handle it directly
+      if (config.installType === 'update') {
+        const state = await this.detectInstallationState(installDir);
+        if (state.type === 'v4_existing') {
+          return await this.performUpdate(config, installDir, state.manifest, spinner);
+        } else {
+          spinner.fail('No existing v4 installation found to update');
+          throw new Error('No existing v4 installation found');
+        }
+      }
+
       // Detect current state
       const state = await this.detectInstallationState(installDir);