improve: use proper file adding function for mini.files multi-selection

- Replace individual send_at_mention calls with _add_paths_to_claude
- Add 100ms delay between files to prevent overwhelming Claude Code
- Include summary message showing how many files were sent
- This ensures all selected files are properly sent and displayed

Fixes issue where only the last file in a multi-selection was shown.

Author: jdurand

lua/claudecode/selection.lua

@@ -675,20 +675,15 @@ function M.send_at_mention_for_visual_selection(line1, line2)
       return false
     end
 
-    -- Send each selected file as a separate at-mention
-    local success_count = 0
-    for _, file_path in ipairs(files) do
-      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
-    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"
+    })
 
     if success_count > 0 then
-      logger.debug("selection", "Successfully sent " .. success_count .. " mini.files selections.")
+      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.")