feat: SEO-friendly share URLs for news posts

- News posts now share as /news/slug-shortguid
- Native posts still use /p/id
- Short guid (8 chars) appended to slug for uniqueness

Example: /news/quebec-vows-protect-aerospace-55217e2d

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/Posts/PostDetailModal.jsx

@@ -695,8 +695,20 @@ export default function PostDetailModal({ post, onClose, onPostUpdated, onPostDe
   }, [postId, liked, post?.guid, post?.app_id]);
 
   const handleShare = useCallback(async () => {
-    if (!postId) return;
-    const shareUrl = `${window.location.origin}/p/${postId}`;
+    if (!postId && !post?.guid) return;
+    let shareUrl;
+    if (post?.app_id && post?.guid) {
+      // SEO-friendly URL: /news/slug-shortguid
+      const slug = (post?.title || "post")
+        .toLowerCase()
+        .replace(/[^a-z0-9]+/g, "-")
+        .replace(/^-+|-+$/g, "")
+        .slice(0, 50);
+      const shortGuid = post.guid.slice(0, 8);
+      shareUrl = `${window.location.origin}/news/${slug}-${shortGuid}`;
+    } else {
+      shareUrl = `${window.location.origin}/p/${postId}`;
+    }
     if (navigator.share) { try { await navigator.share({ title: post?.title, url: shareUrl }); } catch {} }
     else { navigator.clipboard?.writeText(shareUrl); }
     const res = await recordPostShare(postId, post?.guid, post?.app_id);