Improve mobile responsive layout, add mobile stage switcher & collapsible filter bar

public/app.js

@@ -213,8 +213,10 @@ function renderKanbanBoard() {
   for (const st of statuses) {
     const colEl = document.getElementById(`col-${st}`);
     const countEl = document.getElementById(`count-${st}`);
+    const mcountEl = document.getElementById(`mcount-${st}`);
     const list = state.ideas.filter((i) => i.status === st);
     if (countEl) countEl.textContent = list.length;
+    if (mcountEl) mcountEl.textContent = list.length;
     if (!colEl) continue;
 
     if (list.length === 0) {
@@ -1525,6 +1527,21 @@ function bindGlobalEvents() {
   });
 
   // Global Filters
+  document.getElementById("btn-mobile-filter-toggle")?.addEventListener("click", () => {
+    const bar = document.getElementById("global-filter-bar");
+    bar?.classList.toggle("mobile-filters-open");
+  });
+
+  document.querySelectorAll("#mobile-stage-switcher .stage-tab").forEach((tab) => {
+    tab.addEventListener("click", () => {
+      const stage = tab.dataset.mobileStage;
+      document.querySelectorAll("#mobile-stage-switcher .stage-tab").forEach((t) =>
+        t.classList.toggle("active", t === tab)
+      );
+      document.getElementById("kanban-board")?.setAttribute("data-mobile-active-stage", stage);
+    });
+  });
+
   document.getElementById("filter-search")?.addEventListener("input", (e) => {
     state.filters.search = e.target.value;
     loadIdeas();