Decouple i18n from feature modules and fix auth/login UX

Replace hardcoded updateAllText() calls with languageChanged event
pattern so feature modules subscribe independently. Guard all API
calls behind apiKey checks to prevent unauthorized requests when not
logged in. Fix login modal localization, hide tabs when logged out,
clear all panels on logout, and treat profiles with no conditions as
always-true.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/js/app.js

@@ -307,12 +307,12 @@ window.addEventListener('beforeunload', () => {
 // ─── Initialization ───
 
 document.addEventListener('DOMContentLoaded', async () => {
-    // Initialize locale first
-    await initLocale();
-
-    // Load API key from localStorage
+    // Load API key from localStorage before anything that triggers API calls
     setApiKey(localStorage.getItem('wled_api_key'));
 
+    // Initialize locale (dispatches languageChanged which may trigger API calls)
+    await initLocale();
+
     // Restore active tab before showing content to avoid visible jump
     initTabs();
 
@@ -326,7 +326,7 @@ document.addEventListener('DOMContentLoaded', async () => {
     if (!apiKey) {
         setTimeout(() => {
             if (typeof window.showApiKeyModal === 'function') {
-                window.showApiKeyModal('Welcome! Please login with your API key to get started.', true);
+                window.showApiKeyModal(null, true);
             }
         }, 100);
         return;