feat(archive): duration syntax and confirmation prompt (#113)

* feat(s3): create bucket interactively during auth when unconfigured

Problem: when a user runs `:Pending s3 auth` with no bucket configured,
auth succeeds but offers no way to create the bucket. The user must
manually run `aws s3api create-bucket` and update their config.

Solution: add `util.input()` coroutine-aware prompt wrapper and a
`create_bucket()` flow in `s3.lua` that prompts for bucket name and
region, handles the `us-east-1` LocationConstraint quirk, and logs a
config snippet on success. Called automatically from `auth()` when
`sync.s3.bucket` is absent.

* ci: typing

* feat(parse): add `parse_duration_to_days` for duration string conversion

Problem: The archive command accepted only a bare integer for days,
inconsistent with the `+Nd`/`+Nw`/`+Nm` duration syntax used elsewhere.

Solution: Add `parse_duration_to_days()` supporting `Nd`, `Nw`, `Nm`,
and bare integers. Returns nil on invalid input for caller error handling.

* feat(archive): duration syntax and confirmation prompt

Problem: `:Pending archive` accepted only a bare integer for days and
silently deleted tasks with no confirmation, risking accidental data loss.

Solution: Accept duration strings (`7d`, `3w`, `2m`) via
`parse.parse_duration_to_days()`, show a `vim.ui.input` confirmation
prompt before removing tasks, and skip the prompt when zero tasks match.

lua/pending/init.lua

@@ -992,35 +992,67 @@ local function run_sync(backend_name, action)
   backend[action]()
 end
 
----@param days? integer
+---@param msg string
+---@param callback fun()
+local function confirm(msg, callback)
+  vim.ui.input({ prompt = msg .. ' [y/N]: ' }, function(input)
+    if input and input:lower() == 'y' then
+      callback()
+    end
+  end)
+end
+
+---@param arg? string
 ---@return nil
-function M.archive(days)
-  if days == nil then
+function M.archive(arg)
+  local days
+  if arg and arg ~= '' then
+    days = parse.parse_duration_to_days(arg)
+    if not days then
+      log.error('Invalid duration: ' .. arg .. '. Use e.g. 7d, 2w, 3m, or a bare number.')
+      return
+    end
+  else
     days = 30
   end
   local cutoff = os.date('!%Y-%m-%dT%H:%M:%SZ', os.time() - (days * 86400)) --[[@as string]]
   local s = get_store()
   local tasks = s:tasks()
   log.debug(('archive: days=%d cutoff=%s total_tasks=%d'):format(days, cutoff, #tasks))
-  local archived = 0
-  local kept = {}
+  local count = 0
   for _, task in ipairs(tasks) do
     if (task.status == 'done' or task.status == 'deleted') and task['end'] then
       if task['end'] < cutoff then
-        archived = archived + 1
-        goto skip
+        count = count + 1
       end
     end
-    table.insert(kept, task)
-    ::skip::
   end
-  s:replace_tasks(kept)
-  _save_and_notify()
-  log.info('Archived ' .. archived .. ' task' .. (archived == 1 and '' or 's') .. '.')
-  local bufnr = buffer.bufnr()
-  if bufnr and vim.api.nvim_buf_is_valid(bufnr) then
-    buffer.render(bufnr)
+  if count == 0 then
+    log.info('No tasks to archive.')
+    return
   end
+  confirm(
+    'Archive ' .. count .. ' task' .. (count == 1 and '' or 's') .. ' completed/deleted more than ' .. days .. 'd ago?',
+    function()
+      local kept = {}
+      for _, task in ipairs(tasks) do
+        if (task.status == 'done' or task.status == 'deleted') and task['end'] then
+          if task['end'] < cutoff then
+            goto skip
+          end
+        end
+        table.insert(kept, task)
+        ::skip::
+      end
+      s:replace_tasks(kept)
+      _save_and_notify()
+      log.info('Archived ' .. count .. ' task' .. (count == 1 and '' or 's') .. '.')
+      local bufnr = buffer.bufnr()
+      if bufnr and vim.api.nvim_buf_is_valid(bufnr) then
+        buffer.render(bufnr)
+      end
+    end
+  )
 end
 
 ---@return nil
@@ -1342,7 +1374,7 @@ function M.command(args)
     local action = rest:match('^(%S+)')
     run_sync(cmd, action)
   elseif cmd == 'archive' then
-    M.archive(tonumber(rest))
+    M.archive(rest ~= '' and rest or nil)
   elseif cmd == 'due' then
     M.due()
   elseif cmd == 'filter' then