fix(theme): stabilize tenant switch theme propagation and toggle race handling

Task: REVIEW-USER-THEME-001

web/js/components/app-tenant-switcher.js

@@ -44,6 +44,9 @@ const switchTenant = async (link) => {
     if (response.ok) {
       const data = await response.json();
       if (data.ok) {
+        if (data.theme) {
+          document.documentElement.dataset.theme = data.theme;
+        }
         window.location.reload();
       } else {
         warnOnce('FETCH_FAILED', 'Tenant switch failed', { module: 'tenant-switcher', error: data.error });

web/js/components/app-theme-toggle.js

@@ -42,6 +42,7 @@ const initThemeMenu = () => {
     return;
   }
 
+  let pending = false;
   const getCurrent = () => document.documentElement.dataset.theme || '';
   const setActive = (theme) => {
     options.forEach((option) => {
@@ -61,10 +62,12 @@ const initThemeMenu = () => {
   options.forEach((option) => {
     option.addEventListener('click', async (event) => {
       event.preventDefault();
+      if (pending) {return;}
       const next = option.dataset.themeValue || '';
       if (!next) {return;}
       const current = getCurrent();
       if (next === current) {return;}
+      pending = true;
       setTheme(next);
       setIcon(icon, next);
       setActive(next);
@@ -74,6 +77,7 @@ const initThemeMenu = () => {
         setIcon(icon, current);
         setActive(current);
       }
+      pending = false;
     });
   });
 };
@@ -82,12 +86,15 @@ const initThemeToggle = () => {
   const button = optionalEl('[data-theme-toggle]');
   if (!button) {return;}
   const icon = button.querySelector('i');
+  let pending = false;
   const getCurrent = () => document.documentElement.dataset.theme || '';
   setIcon(icon, getCurrent());
 
   button.addEventListener('click', async () => {
+    if (pending) {return;}
     const current = getCurrent();
     const next = isDarkTheme(current) ? 'light' : 'dark';
+    pending = true;
     setTheme(next);
     setIcon(icon, next);
     const ok = await updateTheme(button, next);
@@ -95,6 +102,7 @@ const initThemeToggle = () => {
       setTheme(current);
       setIcon(icon, current);
     }
+    pending = false;
   });
 };