Add search functionality across documentation pages

- Implemented a search button in the header of each documentation page.
- Added a search modal that allows users to input search queries.
- Integrated a JavaScript search feature that fetches and displays results from a new `pages-data.json` file.
- Each documentation page now includes a search overlay for improved navigation.
- Updated the main JavaScript file to handle search logic, including result highlighting and navigation.
- Created a `pages-data.json` file containing metadata for all documentation pages to facilitate search functionality.

docs/css/main.css

@@ -450,3 +450,148 @@ a:hover {
 .theme-toggle:hover {
   opacity: 1;
 }
+
+/* Search button */
+.search-btn {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: none;
+  border: none;
+  color: var(--text);
+  padding: 5px 6px;
+  border-radius: 4px;
+  cursor: pointer;
+  opacity: 0.8;
+}
+
+.search-btn:hover {
+  opacity: 1;
+}
+
+/* Search overlay & modal */
+.search-overlay {
+  display: none;
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.5);
+  z-index: 300;
+  justify-content: center;
+  align-items: flex-start;
+  padding-top: 12vh;
+}
+
+.search-overlay.open {
+  display: flex;
+}
+
+.search-modal {
+  background: var(--bg-secondary);
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  width: 90%;
+  max-width: 560px;
+  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
+  overflow: hidden;
+}
+
+.search-input-wrap {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 12px 16px;
+  border-bottom: 1px solid var(--border);
+}
+
+.search-input-wrap svg {
+  flex-shrink: 0;
+  opacity: 0.5;
+}
+
+#search-input {
+  flex: 1;
+  background: none;
+  border: none;
+  outline: none;
+  color: var(--text-bright);
+  font-size: 1rem;
+  font-family: inherit;
+}
+
+#search-input::placeholder {
+  color: var(--text-muted);
+}
+
+.search-esc {
+  background: var(--bg);
+  color: var(--text-muted);
+  padding: 2px 6px;
+  border-radius: 3px;
+  font-size: 0.7rem;
+  border: 1px solid var(--border);
+}
+
+.search-results {
+  list-style: none;
+  max-height: 50vh;
+  overflow-y: auto;
+  padding: 0;
+  margin: 0;
+}
+
+.search-results:empty::after {
+  content: "";
+  display: none;
+}
+
+.search-results li {
+  padding: 10px 16px;
+  cursor: pointer;
+  border-bottom: 1px solid var(--border);
+}
+
+.search-results li:last-child {
+  border-bottom: none;
+}
+
+.search-results li:hover,
+.search-results li.active {
+  background: var(--bg);
+}
+
+.search-results li .search-result-title {
+  color: var(--text-bright);
+  font-weight: 600;
+  font-size: 0.9rem;
+  margin-bottom: 2px;
+}
+
+.search-results li .search-result-snippet {
+  color: var(--text-muted);
+  font-size: 0.8rem;
+  line-height: 1.4;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  display: -webkit-box;
+  -webkit-line-clamp: 2;
+  -webkit-box-orient: vertical;
+}
+
+.search-results li .search-result-snippet mark {
+  background: rgba(255, 215, 0, 0.3);
+  color: var(--text-bright);
+  border-radius: 2px;
+  padding: 0 1px;
+}
+
+[data-theme="light"] .search-results li .search-result-snippet mark {
+  background: rgba(255, 200, 0, 0.4);
+  color: var(--text);
+}
+
+.search-no-results {
+  padding: 24px 16px;
+  text-align: center;
+  color: var(--text-muted);
+  font-size: 0.9rem;
+}