ui: fix admin/docs theme flash + persist sidebar open/closed state

Theme flash (admin pages, docs, stats, progress — anywhere SSR'd):
the JWT middlewares built the context user WITHOUT the Theme column,
so every page rendering theme-{user.Theme} from c.Get("user") painted
an empty class (:root tokyo-night default) and only settled on the real
theme after initializeTheme -> loadUserTheme round-tripped the server.
Both middlewares now carry liveUser.Theme into the context user;
verified live: /admin /stats /progress /docs /docs-deep /dashboard
/collections all SSR theme-hackerman.

Defense in depth for the same bug: loadTheme() no longer re-applies
localStorage over a server-rendered body theme (applyTheme records even
the default, so any signed-out visit baked tokyo-night into localStorage
and every signed-in page flipped to it post-paint). Public auth/landing
bodies dropped their hardcoded theme classes so ThemeFlashGuard's
pre-paint html class actually governs them; docs theme <select> now
syncs from the body class and re-syncs after the profile fetch.

Sidebar state (the unpleasant part): the app sidebar's openPanel was
reinitialized from the pathname on every load; it now restores from
localStorage ('sidebar-open-panel') with the pathname default as
fallback and -persists every toggle. Docs sidebar sections/groups
carry data-key attributes and toggleCollapsible persists collapsed
state per key ('docs-nav-state'); restoreDocsNav() applies it at init —
server-rendered defaults still govern first visit.

make test green; rendering ownership OK (no new inline scripts); 146
vitests pass; live-verified SSR classes on 7 pages.

web/src/docs.ts

@@ -15,17 +15,70 @@ function toggleSidebar(): void {
   overlay.classList.toggle("hidden");
 }
 
+// Docs sidebar collapse persistence. Rendering ownership: the server
+// renders what is expanded on FIRST paint (navigation.go derives it from
+// the current path); after that, open/closed is client-local state and
+// survives navigation via localStorage. Keys are the data-key attributes
+// rendered by DocsSidebar ("Section" / "Section / Group").
+
+const DOCS_NAV_STORAGE_KEY = "docs-nav-state";
+
+type DocsNavState = Record<string, boolean>;
+
+function readDocsNavState(): DocsNavState {
+  try {
+    const raw = localStorage.getItem(DOCS_NAV_STORAGE_KEY);
+    if (!raw) return {};
+    const parsed = JSON.parse(raw);
+    if (parsed && typeof parsed === "object" && !Array.isArray(parsed)) {
+      return parsed as DocsNavState;
+    }
+  } catch {
+    // Corrupt state falls back to the server-rendered defaults.
+  }
+  return {};
+}
+
+function writeDocsNavState(state: DocsNavState): void {
+  try {
+    localStorage.setItem(DOCS_NAV_STORAGE_KEY, JSON.stringify(state));
+  } catch {
+    // Storage full/blocked: persistence is best-effort.
+  }
+}
+
+function applyCollapsed(items: HTMLElement, collapsed: boolean): void {
+  items.classList.toggle("hidden", collapsed);
+  items.setAttribute("data-collapsed", collapsed ? "true" : "false");
+  const arrow = items.previousElementSibling?.querySelector<HTMLElement>(".section-arrow");
+  if (arrow) {
+    arrow.style.transform = collapsed ? "rotate(-90deg)" : "rotate(0deg)";
+  }
+}
+
+function restoreDocsNav(): void {
+  const state = readDocsNavState();
+  document.querySelectorAll<HTMLElement>("[data-key][data-collapsed]").forEach((items) => {
+    const key = items.getAttribute("data-key");
+    if (key && key in state) {
+      applyCollapsed(items, state[key]);
+    }
+  });
+}
+
 function toggleCollapsible(header: HTMLElement): void {
   const items = header.nextElementSibling as HTMLElement | null;
-  const arrow = header.querySelector<HTMLElement>(".section-arrow");
   if (!items) return;
 
   const isCollapsed = items.getAttribute("data-collapsed") === "true";
 
-  items.classList.toggle("hidden", !isCollapsed);
-  items.setAttribute("data-collapsed", isCollapsed ? "false" : "true");
-  if (arrow) {
-    arrow.style.transform = isCollapsed ? "rotate(0deg)" : "rotate(-90deg)";
+  applyCollapsed(items, !isCollapsed);
+
+  const key = items.getAttribute("data-key");
+  if (key) {
+    const state = readDocsNavState();
+    state[key] = !isCollapsed;
+    writeDocsNavState(state);
   }
 }
 
@@ -116,6 +169,7 @@ function initializeCodeCopyButtons(): void {
 Alpine.data("docs", () => ({
   toggleSidebar,
   toggleCollapsible,
+  restoreDocsNav,
   initializeSearch: initializeDocsSearch,
   initializeCodeCopyButtons,
 }));