fix: implement proper sequential file sending for mini.files

- Use asynchronous sequential sending with 200ms delays
- Ensure proper auto-open behavior by using send_at_mention directly
- Add proper logging and summary messages
- Fix issue where only last file was showing and Claude didn't auto-open

This should now properly send all files with delays and trigger Claude Code opening.

Author: jdurand

lua/claudecode/selection.lua

@@ -675,20 +675,45 @@ function M.send_at_mention_for_visual_selection(line1, line2)
       return false
     end
 
-    -- Use the standard file adding function with delay to properly handle multiple files
-    local success_count, total_count = claudecode_main._add_paths_to_claude(files, {
-      delay = 100, -- 100ms delay between files
-      show_summary = true,
-      context = "mini.files visual selection"
-    })
+    -- Send files sequentially with proper delays
+    local success_count = 0
+    local total_count = #files
 
-    if success_count > 0 then
-      logger.debug("selection", "Successfully sent " .. success_count .. "/" .. total_count .. " mini.files selections.")
-      return true
-    else
-      logger.error("selection", "Failed to send any mini.files selections.")
-      return false
+    local function send_next_file(index)
+      if index > total_count then
+        -- All files processed, show summary
+        if success_count > 0 then
+          local message = success_count == 1 and "Added 1 file from mini.files"
+            or string.format("Added %d files from mini.files", success_count)
+          logger.info("selection", message)
+        else
+          logger.error("selection", "Failed to send any mini.files selections.")
+        end
+        return
+      end
+      
+      local file_path = files[index]
+      local success, error_msg = claudecode_main.send_at_mention(file_path, nil, nil, "ClaudeCodeSend")
+      if success then
+        success_count = success_count + 1
+        logger.debug("selection", "Sent mini.files selection: " .. file_path)
+      else
+        logger.error("selection", "Failed to send mini.files selection " .. file_path .. ": " .. (error_msg or "unknown error"))
+      end
+      
+      -- Send next file after a small delay
+      if index < total_count then
+        vim.defer_fn(function()
+          send_next_file(index + 1)
+        end, 200) -- 200ms delay between files
+      else
+        send_next_file(index + 1) -- Process final summary
+      end
     end
+    
+    -- Start sending files
+    send_next_file(1)
+    return true -- Return immediately, files are sent asynchronously
   end
 
   local sel_to_send