fix(types): correct LuaLS annotations in oauth and gcal

lua/pending/sync/gcal.lua

@@ -169,7 +169,8 @@ function M.push()
         )
 
       if should_delete then
-        local del_err = delete_event(access_token, cal_id, event_id)
+        local del_err =
+          delete_event(access_token, cal_id --[[@as string]], event_id --[[@as string]])
         if del_err then
           vim.notify('pending.nvim: gcal delete failed: ' .. del_err, vim.log.levels.WARN)
         else

lua/pending/sync/oauth.lua

@@ -29,18 +29,18 @@ local M = {}
 
 ---@param args string[]
 ---@param opts? table
----@return vim.SystemCompleted
+---@return { code: integer, stdout: string, stderr: string }
 function M.system(args, opts)
   local co = coroutine.running()
   if not co then
-    return vim.system(args, opts or {}):wait()
+    return vim.system(args, opts or {}):wait() --[[@as { code: integer, stdout: string, stderr: string }]]
   end
   vim.system(args, opts or {}, function(result)
     vim.schedule(function()
       coroutine.resume(co, result)
     end)
   end)
-  return coroutine.yield()
+  return coroutine.yield() --[[@as { code: integer, stdout: string, stderr: string }]]
 end
 
 ---@param fn fun(): nil