feat: redesign website templates with full pages

- Redesigned base.html: dark Minecraft theme, sticky header, responsive grid, cards, server cards with status indicators, profile styles
- index.html: hero section, server list grid, how-to-start steps, features section
- login.html: centered card layout, client-side validation, fetch API
- registration.html: password confirmation, pattern validation, error alerts
- profile.html: new page — skin/cape upload & delete, launcher download links, auth-gated via localStorage token
- templates.go: added /profile route, extended pageData with Username/UUID

internal/templates/templates.go

@@ -14,7 +14,9 @@ import (
 
 // pageData is passed to all templates.
 type pageData struct {
-	Title string
+	Title    string
+	Username string
+	UUID     string
 }
 
 // Handler serves template-rendered pages.
@@ -37,6 +39,7 @@ func (h *Handler) RegisterRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("GET /", h.index)
 	mux.HandleFunc("GET /login", h.loginPage)
 	mux.HandleFunc("GET /register", h.registerPage)
+	mux.HandleFunc("GET /profile", h.profilePage)
 }
 
 // ── Page handlers ──────────────────────────────────────────────
@@ -69,6 +72,14 @@ func (h *Handler) registerPage(w http.ResponseWriter, r *http.Request) {
 	h.render(w, "register.html", pageData{Title: "Регистрация"})
 }
 
+func (h *Handler) profilePage(w http.ResponseWriter, r *http.Request) {
+	if !h.loaded {
+		fallback(w, "Profile")
+		return
+	}
+	h.render(w, "profile.html", pageData{Title: "Профиль"})
+}
+
 // render executes the named template with data, writing to w.
 func (h *Handler) render(w http.ResponseWriter, name string, data pageData) {
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")