Add support for multiple images from Twitter links

- Fetch all images from Twitter syndication API (photos array)
- Store images with unified 'image' media type (first = thumbnail by ID order)
- Display multi-image tweets in grid layout on detail page
- Add hover cycling through images on home grid (2s interval)
- Show image count indicator on multi-image items
- Extract shared downloadAndStoreImages() helper for create/refresh
- Add migration to convert existing thumbnail/gallery types to image
- Make images clickable to open in new tab on detail page

internal/embed/detect.go

@@ -22,13 +22,14 @@ const (
 
 // VideoInfo contains information about an embedded video.
 type VideoInfo struct {
-	Provider     Provider
-	VideoID      string
-	Title        string
-	Description  string
-	ThumbnailURL string
-	EmbedHTML    string
-	VideoURL     string // Direct video URL (for Twitter videos)
+	Provider      Provider
+	VideoID       string
+	Title         string
+	Description   string
+	ThumbnailURL  string   // First/primary thumbnail (for backward compatibility)
+	ThumbnailURLs []string // All thumbnail URLs (for multi-image tweets)
+	EmbedHTML     string
+	VideoURL      string // Direct video URL (for Twitter videos)
 }
 
 var (
@@ -164,8 +165,13 @@ func fetchTwitter(ctx context.Context, tweetID string, originalURL string) (*Vid
 
 	// Find thumbnail and video URL from media
 	var thumbnailURL, videoURL string
+	var thumbnailURLs []string
 	if len(tweet.Photos) > 0 {
 		thumbnailURL = tweet.Photos[0].URL
+		// Collect all photo URLs for multi-image tweets
+		for _, photo := range tweet.Photos {
+			thumbnailURLs = append(thumbnailURLs, photo.URL)
+		}
 	} else if len(tweet.MediaDetails) > 0 {
 		media := tweet.MediaDetails[0]
 		thumbnailURL = media.MediaURLHTTPS
@@ -201,13 +207,14 @@ func fetchTwitter(ctx context.Context, tweetID string, originalURL string) (*Vid
 	description = strings.TrimSpace(description)
 
 	return &VideoInfo{
-		Provider:     ProviderTwitter,
-		VideoID:      tweetID,
-		Title:        title,
-		Description:  description,
-		ThumbnailURL: thumbnailURL,
-		VideoURL:     videoURL,
-		EmbedHTML:    embedHTML,
+		Provider:      ProviderTwitter,
+		VideoID:       tweetID,
+		Title:         title,
+		Description:   description,
+		ThumbnailURL:  thumbnailURL,
+		ThumbnailURLs: thumbnailURLs,
+		VideoURL:      videoURL,
+		EmbedHTML:     embedHTML,
 	}, nil
 }