Add Nebula Browser app, UI and assets

Add initial Nebula Browser project skeleton: CMakeLists to configure and link CEF (including post-build steps to copy runtime and UI files), a Windows CEF-based entry (app/main.cpp) that initializes CEF and loads the bundled UI, and a full ui/ and assets/ tree (HTML, CSS, JS, fonts, icons, and branding images). Update .gitignore to ignore build/out, thirdparty/cef, IDE and common OS artifacts.

ui/js/script.js

@@ -0,0 +1,38 @@
+const SEARCH_URL = 'https://www.google.com/search?q=';
+
+function toNavigationUrl(input) {
+  const value = (input || '').trim();
+  if (!value) return null;
+  if (/^(https?:|file:|data:|blob:)/i.test(value)) return value;
+  if (value.includes('.') && !/\s/.test(value)) return `https://${value}`;
+  return `${SEARCH_URL}${encodeURIComponent(value)}`;
+}
+
+function rememberSearch(input) {
+  if (!input || input.includes('.') || /^(https?:|file:)/i.test(input)) return;
+  try {
+    const current = JSON.parse(localStorage.getItem('searchHistory') || '[]');
+    const next = [input, ...current.filter(item => item !== input)].slice(0, 100);
+    localStorage.setItem('searchHistory', JSON.stringify(next));
+  } catch {}
+}
+
+function navigateTo(input) {
+  const target = toNavigationUrl(input);
+  if (!target) return;
+  rememberSearch(input.trim());
+  window.location.href = target;
+}
+
+window.NebulaCEF = { navigateTo, toNavigationUrl };
+
+document.addEventListener('DOMContentLoaded', () => {
+  const form = document.getElementById('start-form');
+  const urlInput = document.getElementById('start-url');
+  if (!form || !urlInput) return;
+
+  form.addEventListener('submit', event => {
+    event.preventDefault();
+    navigateTo(urlInput.value);
+  });
+});