Add updateassets command with webapp code detection

- Add updateassets command to update plugin files from embedded assets
- Only include webapp assets if plugin manifest indicates webapp code presence
- Compare file contents before updating to avoid unnecessary writes
- Display count of updated files in completion message

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

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

updateassets.go

@@ -0,0 +1,98 @@
+package pluginctl
+
+import (
+	"bytes"
+	"embed"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+//go:embed assets/**/*
+var assetsFS embed.FS
+
+func RunUpdateAssetsCommand(args []string, pluginPath string) error {
+	if len(args) > 0 {
+		return fmt.Errorf("updateassets command does not accept arguments")
+	}
+
+	fmt.Printf("Updating assets in plugin directory: %s\n", pluginPath)
+
+	// Load plugin manifest to check for webapp code
+	manifest, err := LoadPluginManifestFromPath(pluginPath)
+	if err != nil {
+		return fmt.Errorf("failed to load plugin manifest: %w", err)
+	}
+
+	// Check if the plugin has webapp code according to manifest
+	hasWebapp := HasWebappCode(manifest)
+
+	// Counter for updated files
+	var updatedCount int
+
+	// Walk through the embedded assets
+	err = fs.WalkDir(assetsFS, "assets", func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		// Skip the root assets directory
+		if path == "assets" {
+			return nil
+		}
+
+		// Remove the "assets/" prefix to get the relative path
+		relativePath := path[7:] // len("assets/") = 7
+
+		// Skip webapp assets if plugin doesn't have webapp code
+		if !hasWebapp && strings.HasPrefix(relativePath, "webapp") {
+			return nil
+		}
+
+		targetPath := filepath.Join(pluginPath, relativePath)
+
+		if d.IsDir() {
+			// Create directory if it doesn't exist
+			if err := os.MkdirAll(targetPath, 0755); err != nil {
+				return fmt.Errorf("failed to create directory %s: %w", targetPath, err)
+			}
+		} else {
+			// Read file content from embedded FS
+			content, err := assetsFS.ReadFile(path)
+			if err != nil {
+				return fmt.Errorf("failed to read embedded file %s: %w", path, err)
+			}
+
+			// Check if target file exists and compare content
+			existingContent, err := os.ReadFile(targetPath)
+			if err == nil && bytes.Equal(existingContent, content) {
+				// File exists and content is identical, skip update
+				return nil
+			}
+
+			// Create parent directory if it doesn't exist
+			parentDir := filepath.Dir(targetPath)
+			if err := os.MkdirAll(parentDir, 0755); err != nil {
+				return fmt.Errorf("failed to create parent directory %s: %w", parentDir, err)
+			}
+
+			// Write file to target location
+			if err := os.WriteFile(targetPath, content, 0644); err != nil {
+				return fmt.Errorf("failed to write file %s: %w", targetPath, err)
+			}
+			fmt.Printf("Updated file: %s\n", relativePath)
+			updatedCount++
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		return fmt.Errorf("failed to update assets: %w", err)
+	}
+
+	fmt.Printf("Assets updated successfully! (%d files updated)\n", updatedCount)
+	return nil
+}