refactor(init): replace multi-level priority with binary toggle

Problem: <C-a>/<C-x> overrode Vim's native number increment and the
visual g<C-a>/g<C-x> variants added complexity for marginal value.
toggle_complete() left the cursor on the wrong line after re-render.

Solution: remove change_priority/change_priority_visual; add
toggle_priority() (0<->1) mapped to '!', with cursor-follow after
render matching the pattern already used in priority toggle. Add
cursor-follow to toggle_complete() for the same reason. Update plugin
plugs (priority-up/down -> priority) and add 'due'/'undo' to the
:Pending completion list. Update help text accordingly.

lua/pending/init.lua

@@ -52,17 +52,8 @@ function M._setup_buf_mappings(bufnr)
   vim.keymap.set('n', 'g?', function()
     M.show_help()
   end, opts)
-  vim.keymap.set('n', '<C-a>', function()
+  vim.keymap.set('n', '!', function()
-    M.change_priority(1)
+    M.toggle_priority()
-  end, opts)
-  vim.keymap.set('n', '<C-x>', function()
-    M.change_priority(-1)
-  end, opts)
-  vim.keymap.set('v', 'g<C-a>', function()
-    M.change_priority_visual(1)
-  end, opts)
-  vim.keymap.set('v', 'g<C-x>', function()
-    M.change_priority_visual(-1)
   end, opts)
   vim.keymap.set('n', 'D', function()
     M.prompt_date()
@@ -126,10 +117,15 @@ function M.toggle_complete()
   end
   store.save()
   buffer.render(bufnr)
+  for lnum, m in ipairs(buffer.meta()) do
+    if m.id == id then
+      vim.api.nvim_win_set_cursor(0, { lnum, 0 })
+      break
+    end
+  end
 end
 
----@param delta integer
+function M.toggle_priority()
-function M.change_priority(delta)
   local bufnr = buffer.bufnr()
   if not bufnr then
     return
@@ -147,7 +143,7 @@ function M.change_priority(delta)
   if not task then
     return
   end
-  local new_priority = math.max(0, task.priority + delta)
+  local new_priority = task.priority > 0 and 0 or 1
   store.update(id, { priority = new_priority })
   store.save()
   buffer.render(bufnr)
@@ -159,33 +155,6 @@ function M.change_priority(delta)
   end
 end
 
----@param delta integer
-function M.change_priority_visual(delta)
-  local bufnr = buffer.bufnr()
-  if not bufnr then
-    return
-  end
-  local start_row = vim.fn.line("'<")
-  local end_row = vim.fn.line("'>")
-  local meta = buffer.meta()
-  local changed = false
-  for row = start_row, end_row do
-    local m = meta[row]
-    if m and m.type == 'task' and m.id then
-      local task = store.get(m.id)
-      if task then
-        local new_priority = math.max(0, task.priority + delta)
-        store.update(m.id, { priority = new_priority })
-        changed = true
-      end
-    end
-  end
-  if changed then
-    store.save()
-    buffer.render(bufnr)
-  end
-end
-
 function M.prompt_date()
   local bufnr = buffer.bufnr()
   if not bufnr then
@@ -342,10 +311,7 @@ function M.show_help()
     '',
     '<CR>     Toggle complete/uncomplete',
     '<Tab>    Switch category/priority view',
-    '<C-a>    Raise priority level',
+    '!        Toggle urgent',
-    '<C-x>    Lower priority level',
-    'g<C-a>   Raise priority for visual selection',
-    'g<C-x>   Lower priority for visual selection',
     'D        Set due date',
     'U        Undo last write',
     'o / O    Add new task line',
@@ -371,7 +337,7 @@ function M.show_help()
     '',
     'Highlights:',
     '  PendingOverdue   overdue tasks (red)',
-    '  PendingPriority  [N] priority prefix',
+    '  PendingPriority  [!] urgent tasks',
     '',
     'Press q or <Esc> to close',
   }

plugin/pending.lua

@@ -8,7 +8,7 @@ vim.api.nvim_create_user_command('Pending', function(opts)
 end, {
   nargs = '*',
   complete = function(arg_lead, cmd_line)
-    local subcmds = { 'add', 'sync', 'archive' }
+    local subcmds = { 'add', 'sync', 'archive', 'due', 'undo' }
     if not cmd_line:match('^Pending%s+%S') then
       return vim.tbl_filter(function(s)
         return s:find(arg_lead, 1, true) == 1
@@ -30,12 +30,8 @@ vim.keymap.set('n', '<Plug>(pending-view)', function()
   require('pending.buffer').toggle_view()
 end)
 
-vim.keymap.set('n', '<Plug>(pending-priority-up)', function()
+vim.keymap.set('n', '<Plug>(pending-priority)', function()
-  require('pending').change_priority(1)
+  require('pending').toggle_priority()
-end)
-
-vim.keymap.set('n', '<Plug>(pending-priority-down)', function()
-  require('pending').change_priority(-1)
 end)
 
 vim.keymap.set('n', '<Plug>(pending-date)', function()