feat(links): move friend links to native WordPress links with review flow

- enable the native Links manager and drop the custom friend-link option/REST path
- add per-page link settings for the friends template
- render link categories from get_bookmarks() with search and page-content options
- add a validated public link submission endpoint with logo upload, captcha, rate limiting and duplicate checks
- create pending links for review and notify administrators by email and in-app message
- add native Links admin pending count, columns and edit notes
- cover the new submission and cleanup contracts

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

assets/css/routes/friends.css

@@ -1,74 +0,0 @@
-/**
- * Jio Friends Page — 友情链接页样式
- *
- * @package Jio
- */
-
-.friends-grid {
-    display: grid;
-    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
-    gap: var(--space-4);
-    margin-top: var(--space-6);
-}
-
-.friend-card {
-    display: flex;
-    align-items: center;
-    gap: var(--space-4);
-    padding: var(--card-padding);
-    background: var(--surface-1);
-    border: 1px solid var(--color-line);
-    border-radius: var(--radius-lg);
-    box-shadow: var(--shadow-sm);
-    text-decoration: none;
-    color: var(--color-ink-2);
-    transition: box-shadow var(--dur) var(--ease), border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
-}
-
-.friend-card:hover {
-    box-shadow: var(--shadow);
-    border-color: var(--color-primary-soft);
-    transform: none;
-}
-
-.friend-card__avatar {
-    width: 48px;
-    height: 48px;
-    border-radius: var(--radius-avatar, 50%);
-    object-fit: cover;
-    flex-shrink: 0;
-    background: var(--surface-2);
-}
-
-.friend-card__info {
-    flex: 1;
-    min-width: 0;
-}
-
-.friend-card__name {
-    font-size: var(--text-base);
-    font-weight: 600;
-    color: var(--color-ink);
-    margin: 0 0 4px;
-    overflow: hidden;
-    text-overflow: ellipsis;
-    white-space: nowrap;
-}
-
-.friend-card__desc {
-    font-size: var(--text-sm);
-    color: var(--color-ink-3);
-    margin: 0;
-    display: -webkit-box;
-    -webkit-line-clamp: 2;
-    -webkit-box-orient: vertical;
-    overflow: hidden;
-    line-height: var(--leading-snug);
-}
-
-/* Responsive */
-@media (max-width: 640px) {
-    .friends-grid {
-        grid-template-columns: 1fr;
-    }
-}

assets/css/routes/links.css

@@ -148,6 +148,17 @@
 	margin-bottom: 6px;
 }
 
+.jio-links-submit-status {
+	margin: 10px 0;
+	font-size: 0.92em;
+}
+
+.jio-links-logo-preview {
+	width: 88px;
+	height: 88px;
+	object-fit: cover;
+}
+
 /* ---- search cover ---- */
 .link-page-search-cover.page-cover {
 	position: relative;