feat: implement serve mode with file watching

- Add fsnotify for file watching in serve mode
- Create watcher.go for content directory monitoring
- Update serve mode to generate initial output and watch for changes
- Add route to serve generated HTML files from output directory
- File changes trigger automatic regeneration

Co-Authored-By: Claude (glm-5) <noreply@anthropic.com>

go.mod

@@ -7,4 +7,8 @@ require (
 	gopkg.in/yaml.v2 v2.4.0
 )
 
-require github.com/yuin/goldmark v1.7.16 // indirect
+require (
+	github.com/fsnotify/fsnotify v1.9.0 // indirect
+	github.com/yuin/goldmark v1.7.16 // indirect
+	golang.org/x/sys v0.13.0 // indirect
+)

go.sum

@@ -1,7 +1,11 @@
+github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
+github.com/fsnotify/fsnotify v1.9.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
 github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
 github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
 github.com/yuin/goldmark v1.7.16 h1:n+CJdUxaFMiDUNnWC3dMWCIQJSkxH4uz3ZwQBkAlVNE=
 github.com/yuin/goldmark v1.7.16/go.mod h1:ip/1k0VRfGynBgxOz0yCqHrbZXhcjxyuS66Brc7iBKg=
+golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
+golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=

main.go

@@ -52,6 +52,21 @@ func runCLIMode() {
 func runServeMode() {
 	fmt.Println("Running in Serve mode...")
 
+	// Generate initial output
+	fmt.Println("Generating initial output...")
+	if err := generateOutput(); err != nil {
+		fmt.Printf("Error generating initial output: %s\n", err)
+	}
+
+	// Start file watcher for live reload
+	watcher, err := startWatcher()
+	if err != nil {
+		fmt.Printf("Warning: Failed to start file watcher: %s\n", err)
+	}
+	if watcher != nil {
+		defer watcher.Close()
+	}
+
 	// Create a channel to receive the OS signals
 	sc := make(chan os.Signal, 1)
 	signal.Notify(sc, syscall.SIGINT, syscall.SIGTERM)
@@ -68,7 +83,7 @@ func runServeMode() {
 	defer shCancel()
 
 	// Shutdown the HTTP server
-	err := ws.HTTPServer.Shutdown(shCtx)
+	err = ws.HTTPServer.Shutdown(shCtx)
 	if err != nil {
 		fmt.Printf("Server shutdown error: %s", err)
 		os.Exit(1)

routes.go

@@ -1,7 +1,14 @@
 package main
 
-import "github.com/gorilla/mux"
+import (
+	"net/http"
+
+	"github.com/gorilla/mux"
+)
 
 func (s *WebServer) Routes(r *mux.Router) {
 	r.HandleFunc("/version", handleVersion).Methods("GET")
+
+	// Serve generated HTML files from output directory
+	r.PathPrefix("/").Handler(http.StripPrefix("/", http.FileServer(http.Dir(outputPath))))
 }

watcher.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/fsnotify/fsnotify"
+)
+
+// startWatcher starts watching the content directory for changes
+func startWatcher() (*fsnotify.Watcher, error) {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return nil, fmt.Errorf("failed to create watcher: %w", err)
+	}
+
+	// Add content directory to watcher
+	err = watcher.Add(contentPath)
+	if err != nil {
+		watcher.Close()
+		return nil, fmt.Errorf("failed to watch content directory: %w", err)
+	}
+
+	fmt.Printf("Watching %s for changes...\n", contentPath)
+
+	// Start goroutine to handle events
+	go func() {
+		for {
+			select {
+			case event, ok := <-watcher.Events:
+				if !ok {
+					return
+				}
+				// Only process write and create events for .md files
+				if event.Has(fsnotify.Write) || event.Has(fsnotify.Create) {
+					fmt.Printf("File changed: %s\n", event.Name)
+					// Regenerate output
+					if err := generateOutput(); err != nil {
+						fmt.Printf("Error regenerating: %s\n", err)
+					}
+				}
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					return
+				}
+				fmt.Printf("Watcher error: %s\n", err)
+			}
+		}
+	}()
+
+	return watcher, nil
+}