feat(textobj): add debug mode, rename priority view buffer

Problem: the ]] motion reportedly lands one line past the header in
some environments, and ]t/[t may not override Neovim defaults. No
way to diagnose these at runtime. Also, pending://priority is a poor
buffer name for the flat ranked view.

Solution: add a debug config option (vim.g.pending = { debug = true })
that logs meta state, cursor positions, and mapping registration to
:messages at DEBUG level. Rename the buffer from pending://priority to
pending://queue. Internal view identifier stays 'priority'.

lua/pending/buffer.lua

@@ -223,7 +223,8 @@ function M.render(bufnr)
   end
 
   current_view = current_view or config.get().default_view
-  vim.api.nvim_buf_set_name(bufnr, 'pending://' .. current_view)
+  local view_label = current_view == 'priority' and 'queue' or current_view
+  vim.api.nvim_buf_set_name(bufnr, 'pending://' .. view_label)
   local tasks = store.active_tasks()
 
   local lines, line_meta