Keep sidebar controls in dedicated left rail

public/app.js

@@ -53,6 +53,7 @@ const darkContrastSelect = document.querySelector("#darkContrastSelect");
 const catalogScreen = document.querySelector(".catalog-screen");
 const secondaryPanelToggle = document.querySelector("#secondaryPanelToggle");
 const mainWorkspaceToggle = document.querySelector("#mainWorkspaceToggle");
+let sidebarUserClosed = false;
 const nativeFetch = window.fetch.bind(window);
 window.fetch = (input, init = {}) => {
     const url = typeof input === "string" ? input : input.url;
@@ -225,7 +226,6 @@ lightContrastSelect.addEventListener("change", saveAppearance);
 darkContrastSelect.addEventListener("change", saveAppearance);
 loadDatabaseMode();
 syncSidebarForViewport();
-window.matchMedia("(min-width: 981px)").addEventListener("change", syncSidebarForViewport);
 setTimeout(() => {
     if (manufacturerSelect.value) {
         loadMappingSources();
@@ -852,12 +852,13 @@ function toggleParserDrawer() {
     parserDrawerToggle.querySelector(".drawer-chevron").textContent = isOpen ? "⌄" : "⌃";
 }
 function syncSidebarForViewport() {
-    if (window.matchMedia("(min-width: 981px)").matches)
+    if (window.matchMedia("(min-width: 981px)").matches && !sidebarUserClosed)
         openSidebar();
     else
         closeSidebar();
 }
 function openSidebar() {
+    sidebarUserClosed = false;
     sidebarDrawer.classList.add("is-open");
     sidebarOverlay.hidden = false;
     sidebarOpenButton.hidden = true;
@@ -866,6 +867,7 @@ function openSidebar() {
     catalogScreen.classList.remove("sidebar-collapsed");
 }
 function closeSidebar() {
+    sidebarUserClosed = true;
     sidebarDrawer.classList.remove("is-open");
     sidebarOverlay.hidden = true;
     sidebarOpenButton.hidden = false;