Fix image gallery deduplication for absolute vs relative URLs

- Extract filename only (not full path) for deduplication
- Same image as https://domain/path/file.jpg and /path/file.jpg
  were not being deduplicated because full paths differ
- Updated both PostDetailModal.jsx and markerManager.js
- Added fetchPostById to get full post data with image_urls

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

src/components/Map/markerManager.js

@@ -789,11 +789,14 @@ function collectGalleryImages(post) {
   const seen = new Set();
   const seenBase = new Set();
   // Get base filename without size suffix to detect same image in different sizes
+  // Extract just the filename (not full path) to handle absolute vs relative URL dedup
   // Handles both long (_large, _medium, _small) and short (_l, _m, _s) variants
   const getBase = (url) => {
     if (!url) return '';
-    return url.replace(/[-_](large|medium|small|thumb|thumbnail|l|m|s)(\.[^.]+)?$/i, '$2')
-              .replace(/\?.*$/, ''); // Remove query params
+    // Extract just the filename, remove path and domain
+    const filename = url.split('/').pop() || url;
+    return filename.replace(/[-_](large|medium|small|thumb|thumbnail|l|m|s)(\.[^.]+)?$/i, '$2')
+                   .replace(/\?.*$/, ''); // Remove query params
   };
   const add = (value) => {
     const normalized = normalizeImageUrl(value);

src/components/Posts/PostDetailModal.jsx

@@ -17,6 +17,7 @@ import {
   deletePost,
   updatePostVisibility,
   fetchProfile,
+  fetchPostById,
 } from "../../api/client";
 
 // ============================================================================
@@ -567,6 +568,7 @@ export default function PostDetailModal({ post, onClose, onPostUpdated, onPostDe
   const [showComments, setShowComments] = useState(true);
   const [showEdit, setShowEdit] = useState(false);
   const [showDelete, setShowDelete] = useState(false);
+  const [fullPost, setFullPost] = useState(null); // Full post data fetched from API
   const [editTitle, setEditTitle] = useState(post?.title || "");
   const [editSnippet, setEditSnippet] = useState(post?.snippet || "");
   const [editVisibility, setEditVisibility] = useState(post?.visibility || "public");
@@ -585,6 +587,9 @@ export default function PostDetailModal({ post, onClose, onPostUpdated, onPostDe
   const config = getCategoryConfig(post?.category);
   const author = post?.author || post?.username || post?.source_name || t("common.anon");
 
+  // Merged post data: prefer fullPost (fetched from API) over initial post prop
+  const postData = useMemo(() => fullPost ?? post, [fullPost, post]);
+
   // Media gallery - dedupe by base filename (ignore size variants like _large, _medium, _small, _l, _m, _s)
   // Note: media_urls is for videos only, image_urls is for images
   const gallery = useMemo(() => {
@@ -592,10 +597,12 @@ export default function PostDetailModal({ post, onClose, onPostUpdated, onPostDe
     const seenBase = new Set();
     const images = [];
     const getBase = (url) => {
+      // Extract just the filename, remove path and domain
+      const filename = url.split('/').pop() || url;
       // Remove size suffixes to detect same image in different sizes
       // Handles both long (_large, _medium, _small) and short (_l, _m, _s) variants
-      return url.replace(/[-_](large|medium|small|thumb|thumbnail|l|m|s)(\.[^.]+)?$/i, '$2')
-                .replace(/\?.*$/, ''); // Remove query params
+      return filename.replace(/[-_](large|medium|small|thumb|thumbnail|l|m|s)(\.[^.]+)?$/i, '$2')
+                     .replace(/\?.*$/, ''); // Remove query params
     };
     const add = (url) => {
       const n = normalizeMediaUrl(url);
@@ -608,11 +615,11 @@ export default function PostDetailModal({ post, onClose, onPostUpdated, onPostDe
       images.push(n);
     };
     // Add from image_urls array first (user-uploaded galleries) - NOT media_urls (that's for videos)
-    post?.image_urls?.forEach(add);
+    postData?.image_urls?.forEach(add);
     // Then single images (prefer large > medium > small)
-    [post?.image_large, post?.image_medium, post?.image_small, post?.image_url, post?.image].forEach(add);
+    [postData?.image_large, postData?.image_medium, postData?.image_small, postData?.image_url, postData?.image].forEach(add);
     return images;
-  }, [post]);
+  }, [postData]);
 
   // Initial data fetch
   useEffect(() => {
@@ -624,6 +631,14 @@ export default function PostDetailModal({ post, onClose, onPostUpdated, onPostDe
     fetchPostTruth(postId).then(res => { if (res) setTruth({ score: res.truth_score ?? res.user_score ?? 50, count: res.vote_count ?? 0 }); });
   }, [postId]);
 
+  // Fetch full post data from API to get image_urls (map markers don't have it)
+  useEffect(() => {
+    if (!postId) return;
+    fetchPostById(postId).then(fresh => {
+      if (fresh) setFullPost(fresh);
+    });
+  }, [postId]);
+
   // Fetch author avatar
   useEffect(() => {
     const authorName = post?.author || post?.username;