fix #221: scale image pastes, drop text box, fix raw view and size

- image pastes render the image scaled to fit the viewer box (aspect
  ratio preserved, max-height 70vh), no text/code box below it
- link pill moved under the image as a small inline chip
- /raw serves image attachment bytes as an image instead of empty text
- view details size reports the actual attachment file size

internal/web/web.go

@@ -252,20 +252,35 @@ func (h *Handlers) renderPaste(w http.ResponseWriter, row *store.PasteRow, justC
 		http.Error(w, "db error", 500)
 		return
 	}
+	// #221: image attachments render the image, not a text/code box. Size
+	// comes from the attachment's actual file size, not the text content.
+	attImage := false
+	if attachment != nil {
+		switch attachment.Mime {
+		case "image/png", "image/jpeg", "image/gif", "image/webp":
+			attImage = true
+		}
+	}
+	sizeHuman := humanSize(len(row.Content))
+	lineCount := lines
+	if attachment != nil {
+		sizeHuman = attachment.SizeHuman
+		lineCount = 1
+	}
 	data := map[string]any{
 		"Page":          "paste",
 		"ID":            row.ID,
 		"Title":         row.Title.String,
 		"Language":      row.Language.String,
 		"StatsSummary":  summary,
-		"SizeHuman":     humanSize(len(row.Content)),
+		"SizeHuman":     sizeHuman,
 		"HasPassword":   row.PasswordHash.Valid,
 		"BurnAfterRead": row.BurnAfterRead,
 		"CustomSlug":    row.CustomSlug.String,
 		"ContentHTML":   template.HTML(langpkg.HighlightCode(row.Content, row.Language.String)), // safe: HighlightCode escapes all non-span text
 		"ContentAttr":   row.Content,
 		"Gutter":        strings.TrimSuffix(gutter, "\n"),
-		"LineCount":     lines,
+		"LineCount":     lineCount,
 		"SizeBytes":     len(row.Content),
 		"CreatedAgo":    agoString(row.CreatedAt),
 		"CreatedAtUnix": row.CreatedAt,
@@ -279,6 +294,7 @@ func (h *Handlers) renderPaste(w http.ResponseWriter, row *store.PasteRow, justC
 		"ReadsTotal":    int(row.ReadsLimit.Int64),
 		"JustCreated":   justCreated,
 		"Attachment":    attachment,
+		"AttachmentImage": attImage,
 		"Host":          "this host",
 	}
 	h.renderPage(w, "paste.html", data)