refactor: message content (#1424)

lua/avante/providers/gemini.lua

@@ -33,9 +33,15 @@ function M.parse_messages(opts)
       end
     end
     prev_role = role
-    table.insert(contents, { role = M.role_map[role] or role, parts = {
-      { text = message.content },
-    } })
+    local parts = {}
+    for _, item in ipairs(message.content) do
+      if type(item) == "string" then
+        table.insert(parts, { text = item })
+      elseif item.type == "text" then
+        table.insert(parts, { text = item.text })
+      end
+    end
+    table.insert(contents, { role = M.role_map[role] or role, parts = parts })
   end)
 
   if Clipboard.support_paste_image() and opts.image_paths then