fix: add main.go to git

.gitignore

@@ -1,2 +1,2 @@
-nucleus
+/nucleus
 cmd/nucleus/dist

cmd/nucleus/main.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"embed"
+	"io/fs"
+	"log"
+	"net/http"
+	"os"
+
+	"nucleus/internal/api"
+	"nucleus/internal/db"
+	"nucleus/internal/scheduler"
+)
+
+//go:embed dist/*
+var staticFiles embed.FS
+
+type spaHandler struct {
+	staticPath string
+	indexPath  string
+	fs         http.FileSystem
+}
+
+func (h spaHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	path := r.URL.Path
+
+	// Check if file exists
+	f, err := h.fs.Open(path)
+	if os.IsNotExist(err) {
+		// fallback to index.html
+		r.URL.Path = "/"
+	} else if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	} else {
+		// If file exists, check if it's a directory
+		stat, err := f.Stat()
+		if err == nil && stat.IsDir() {
+			r.URL.Path = "/"
+		}
+		f.Close()
+	}
+
+	http.FileServer(h.fs).ServeHTTP(w, r)
+}
+
+func main() {
+	db.InitDB("app.db")
+	scheduler.InitScheduler()
+
+	mux := http.NewServeMux()
+
+	api.RegisterRoutes(mux)
+
+	// Setup embedded SPA
+	distFS, err := fs.Sub(staticFiles, "dist")
+	if err != nil {
+		// If running locally without build, this might fail, fallback to a simple message
+		log.Println("dist/ not found in embedded filesystem. Ensure frontend is built before compiling. Serving API only.")
+	} else {
+		spa := spaHandler{staticPath: "/", indexPath: "index.html", fs: http.FS(distFS)}
+		mux.Handle("/", spa)
+	}
+
+	log.Println("Starting server on :8080")
+	if err := http.ListenAndServe(":8080", mux); err != nil {
+		log.Fatal(err)
+	}
+}