Apply LotusGuild design system convergence (aesthetic_diff.md)

CSS (style.css):
- §1: Add unified naming aliases (--terminal-green, --bg-primary, etc.)
- §2: Upgrade borders: modal 1px→3px double, btn/btn-sm/inputs 1px→2px
- §3: Add [ ] bracket decorations to .btn classes; primary keeps > prefix;
  hover lift -1px→-2px; padding 6px 14px→5px 12px
- §4: Fix glow definitions from 2-layer rgba to 3-layer solid stack
- §5: Section headers now symmetric ╠═══ TITLE ═══╣ (was one-sided)
- §6+§7: Modal border 3px double, corners ┌┐→╔╗, add glow shadow
- §11: Nav active state now amber tint (was green); hover remains green
- §15: Scanline opacity 0.13→0.15; flicker delay 45s→30s

JS (app.js):
- §18: Replace custom showToast() with lt.toast.* delegate wrapper

Templates (base.html):
- Load base.css and base.js (symlinked from web_template)
- Add lt-boot overlay for boot sequence animation (§13)

README: Remove completed pending convergence items

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

static/app.js

@@ -1,18 +1,11 @@
 'use strict';
 
-// ── Toast notifications ───────────────────────────────────────────────
+// ── Toast notifications — delegates to lt.toast from base.js ─────────
 function showToast(msg, type = 'success') {
-  let container = document.querySelector('.toast-container');
-  if (!container) {
-    container = document.createElement('div');
-    container.className = 'toast-container';
-    document.body.appendChild(container);
-  }
-  const toast = document.createElement('div');
-  toast.className = `toast toast-${type}`;
-  toast.textContent = msg;
-  container.appendChild(toast);
-  setTimeout(() => toast.remove(), 3500);
+  if (type === 'error')   return lt.toast.error(msg);
+  if (type === 'warning') return lt.toast.warning(msg);
+  if (type === 'info')    return lt.toast.info(msg);
+  return lt.toast.success(msg);
 }
 
 // ── Dashboard auto-refresh ────────────────────────────────────────────