Add static files and HTML templates for web UI

Embedded Tailwind CSS and login/generator templates.
Self-contained with no external dependencies.

internal/static/static.go

@@ -0,0 +1,21 @@
+// Package static provides embedded static files for the web UI.
+package static
+
+import (
+	"embed"
+	"io/fs"
+	"net/http"
+)
+
+//go:embed *.js
+var files embed.FS
+
+// FS returns the embedded filesystem containing static files.
+func FS() fs.FS {
+	return files
+}
+
+// Handler returns an http.Handler that serves static files.
+func Handler() http.Handler {
+	return http.FileServer(http.FS(files))
+}