heph.nvim: :Heph journals — recent-days picker with preview + @create

A dailies picker (zkd-style): lists the last `journal_days` (default 7) days
newest-first, previews existing journals and shows "@create" for new ones, and
opens the chosen day (creating if new). Journals resolve by their ISO-date
title, so no new RPC is needed. picker.select gains an optional Telescope
preview pane. e2e covers the recent-days list (exists/@create across a month
boundary) and open-on-pick via a stubbed vim.ui.select.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

heph.nvim/lua/heph/command.lua

@@ -19,6 +19,9 @@ M.subs = {
   journal = function(args)
     require("heph.journal").open(args[1])
   end,
+  journals = function()
+    require("heph.journal").pick()
+  end,
   follow = function()
     require("heph.link").follow()
   end,