refactor: Add scrollToSection and fix missing functions

- Add scrollToSection() to utils._hs (was missing after cv-functions.js removal)
- Move error toast close handler to inline hyperscript
- Remove initMenuCloseOnClick() - now integrated into scrollToSection()
- Remove initErrorToastClose() - now hyperscript inline handler
- Remove unused initScrollBehaviorJS() fallback (~70 lines dead code)

This fixes the navigation menu scroll functionality and eliminates
more JavaScript in favor of hyperscript.

static/hyperscript/utils._hs

@@ -170,6 +170,24 @@ def setFooterHover(show)
   end
 end
 
+-- ==============================================================================
+-- NAVIGATION SCROLL
+-- ==============================================================================
+-- Smooth scroll to a section by ID
+def scrollToSection(evt, sectionId)
+  if evt then call evt.preventDefault() end
+  set el to document.getElementById(sectionId)
+  if el is not null
+    call el.scrollIntoView({ behavior: 'smooth' })
+    -- Close the menu after navigation
+    set menu to document.querySelector('.navigation-menu')
+    if menu is not null
+      remove .menu-hover from menu
+      remove .menu-open from menu
+    end
+  end
+end
+
 -- ==============================================================================
 -- KEYBOARD SHORTCUTS
 -- ==============================================================================