Fix: resolve JS SyntaxErrors that crashed entire window.lt namespace

Root cause: two SyntaxErrors prevented the IIFE from completing,
meaning window.lt was never created and all features were broken.

Fixes applied:
1. CRITICAL: Renamed auth's apiFetch redeclaration → _apiFetchAuth
   (duplicate function declaration in strict-mode IIFE = SyntaxError)
2. CRITICAL: Renamed toast queue vars (_toastQueue/_toastActive already
   declared by original showToast in outer scope = SyntaxError)
   Replaced heavy queue wrapper with lightweight progress-bar injector
3. timer.countdown: classList.add(urgentClass) throws on space-separated
   class string — split/filter/forEach now used
4. contextMenu: _ctxItems declared as [] but used as string-keyed object
   — changed to {}
5. Split pane divider: background was border-dim (7% opacity, invisible)
   — raised to border-color (16%), added ::before hit-area expansion,
   hover state uses accent-cyan for clear visual feedback
6. Light theme: html background-image was hardcoded cyan rgba, didn't
   update with data-theme — added explicit html[data-theme="light"] rule
7. Light theme: .lt-header background was hardcoded rgba(3,5,8,0.96)
   — added explicit light-mode override

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

base.js

@@ -1582,7 +1582,7 @@
      items = [{ label, icon, kbd, danger, divider, action }]
      ================================================================ */
   let _ctxMenu = null;
-  let _ctxItems = [];
+  const _ctxItems = {};
   function _ctxShow(x, y, items) {
     if (!_ctxMenu) {
       _ctxMenu = document.createElement('div');
@@ -2028,49 +2028,31 @@
   };
 
   /* ================================================================
-     MODULE 47 — TOAST QUEUE (enhanced dispatch)
-     Wraps existing toast module with max-stack + progress bars
+     MODULE 47 — TOAST ENHANCEMENTS
+     Adds a drain progress bar to each toast.
+     The original showToast already handles queuing (section 2).
      ================================================================ */
-  const _toastMaxStack = 5;
-  const _toastQueue    = [];
-  let   _toastActive   = 0;
-  const _origToast     = Object.assign({}, toast);
-
-  function _toastEnqueue(type, msg, dur = 4000) {
-    if (_toastActive >= _toastMaxStack) {
-      _toastQueue.push({ type, msg, dur });
-      return;
-    }
-    _toastActive++;
-    const id = _origToast[type] ? _origToast[type](msg, dur) : _origToast.info(msg, dur);
-    // Add progress bar to the toast element
-    setTimeout(() => {
-      const toastEl = document.querySelector(`#lt-toast-container .lt-toast:last-child`);
-      if (toastEl && !toastEl.querySelector('.lt-toast-progress')) {
+  // Patch showToast to inject a progress bar after each toast is created
+  const _origShowToast = showToast;
+  function showToast(message, type, duration) {
+    duration = duration || 4000;
+    const result = _origShowToast(message, type, duration);
+    // Inject drain bar into the most recently added toast
+    requestAnimationFrame(() => {
+      const container = document.getElementById('lt-toast-container');
+      if (!container) return;
+      const toasts = container.querySelectorAll('.lt-toast');
+      const last = toasts[toasts.length - 1];
+      if (last && !last.querySelector('.lt-toast-progress')) {
         const bar = document.createElement('div');
         bar.className = 'lt-toast-progress';
-        bar.style.animationDuration = dur + 'ms';
-        toastEl.appendChild(bar);
+        bar.style.animationDuration = duration + 'ms';
+        last.appendChild(bar);
       }
-    }, 20);
-    setTimeout(() => {
-      _toastActive = Math.max(0, _toastActive - 1);
-      if (_toastQueue.length) {
-        const next = _toastQueue.shift();
-        _toastEnqueue(next.type, next.msg, next.dur);
-      }
-    }, dur + 400);
-    return id;
+    });
+    return result;
   }
 
-  // Override toast methods to use queue
-  ['success','error','warning','info'].forEach(t => {
-    if (toast[t]) {
-      const orig = toast[t].bind(toast);
-      toast[t] = (msg, dur) => _toastEnqueue(t, msg, dur || 4000);
-    }
-  });
-
   /* ================================================================
      MODULE 48 — SIDEBAR SUBMENUS
      Auto-inits .lt-sidebar-group elements.
@@ -2358,7 +2340,7 @@
           clearInterval(handle);
           return;
         }
-        if (diff <= urgent) dom.classList.add(urgentClass);
+        if (diff <= urgent) urgentClass.split(/\s+/).filter(Boolean).forEach(c => dom.classList.add(c));
         const h = Math.floor(diff / 3600), m = Math.floor((diff % 3600) / 60), s = diff % 60;
         dom.textContent = [h, m, s].map(n => String(n).padStart(2, '0')).join(':');
       }
@@ -2551,18 +2533,15 @@
     isExpiringSoon: (secs = 60) => _authExpiry > 0 && Date.now() >= _authExpiry - secs * 1000,
   };
 
-  // Patch lt.api to inject Authorization header and auto-refresh
-  const _origApiFetch = apiFetch;
-  async function apiFetch(method, url, body) {
-    if (_authAccess) {
-      if (auth.isExpiringSoon()) await auth.refresh();
-    }
+  // Patch lt.api — auth-aware wrapper (renamed to avoid strict-mode duplicate declaration)
+  async function _apiFetchAuth(method, url, body) {
+    if (_authAccess && auth.isExpiringSoon()) await auth.refresh();
     const opts = { method, headers: Object.assign({ 'Content-Type': 'application/json' }, csrfHeaders()) };
     if (_authAccess) opts.headers['Authorization'] = 'Bearer ' + _authAccess;
     if (body !== undefined) opts.body = JSON.stringify(body);
     let resp;
     try { resp = await fetch(url, opts); } catch (err) { throw new Error('Network error: ' + err.message); }
-    // Auto-retry once on 401 after token refresh
+    // Auto-retry once on 401 after silent token refresh
     if (resp.status === 401 && _authRefresh) {
       const ok = await auth.refresh();
       if (ok) {
@@ -2575,12 +2554,11 @@
     if (!resp.ok) throw new Error(data.error || data.message || 'HTTP ' + resp.status);
     return data;
   }
-  // Re-point api methods to patched apiFetch
-  api.get    = url     => apiFetch('GET',    url);
-  api.post   = (u, b)  => apiFetch('POST',   u, b);
-  api.put    = (u, b)  => apiFetch('PUT',    u, b);
-  api.patch  = (u, b)  => apiFetch('PATCH',  u, b);
-  api.delete = (u, b)  => apiFetch('DELETE', u, b);
+  api.get    = url     => _apiFetchAuth('GET',    url);
+  api.post   = (u, b)  => _apiFetchAuth('POST',   u, b);
+  api.put    = (u, b)  => _apiFetchAuth('PUT',    u, b);
+  api.patch  = (u, b)  => _apiFetchAuth('PATCH',  u, b);
+  api.delete = (u, b)  => _apiFetchAuth('DELETE', u, b);
 
   /* ================================================================
      MODULE 54 — MARKDOWN RENDERER