Strip the bash-bin compatibility layer from Menu.qml

With bin/omarchy-menu gone there's no caller that summons the menu by
writing a JSON tempfile and polling a done file. Drop everything that
existed only to support that handshake:

  - menuJsonFile / menuJsonFileView / loadMenuJson / openMenu(json,...)
  - pendingSelectionFile / pendingDoneFile / selectionFile / doneFile
  - mergeProviderJson (the JSON-wrapper for provider output)
  - applyProc / releaseProc / doneFilesToRelease / finishDoneFile /
    releaseNextDoneFile / resetRequest / requestActive / closeMenu
  - the menuBin property pointing at the deleted bin

applySelected is now four lines (close + execDetached); cancel is two
(close + clear filter). open() takes either {menu: id} or a bare initial
menu name, and hands off to openExistingMenu which uses the cached items
from the JSONC FileViews.

Net: 91 lines smaller, no perf change.

default/omarchy/omarchy-menu.jsonc

@@ -7,7 +7,7 @@
   // Dotted IDs define the tree. Use provider:"name" only when the submenu
   // calls provider_name() or a command named "name" to return JSON rows.
   // Optional fields:
-  //   aliases        alternate `omarchy-menu <name>` routes; also searchable
+  //   aliases        alternate `omarchy-shell-ipc menu summon <name>` routes; also searchable
   //   keywords       extra search terms beyond id/label/aliases
   //   when           shell condition; hide row when it fails
   //   checked        shell condition; append ✓ when it succeeds