Vendor helgoboss/helgobox (ReaLearn) as basis for custom UI fork

Stripped upstream git history; starting point for replacing the native
SWELL/Win32 mapping UI with something more suited to bulk editing.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

plugin-reaper-realearn/doc/helgobox/modules/ROOT/pages/reaper-actions.adoc

@@ -0,0 +1,23 @@
+= REAPER actions
+
+== General actions
+
+Helgobox provides a few global REAPER actions.
+
+You can find those actions directly in the menu menu:Extensions[Helgobox].
+Alternatively, search for "helgobox" in REAPER's action list (menu:Actions[Show action list...]).
+
+[[show-welcome-screen]] Helgobox/General: Show welcome screen::
+Shows the xref:plug-in/user-interface/welcome-dialog.adoc[] that was displayed after the first installation of Helgobox.
+
+[[toggle-app-focus]] Helgobox/General: Toggle app focus::
+Switches focus between REAPER and the xref:app.adoc[].
++
+The default shortcut is kbd:[Shift+Cmd/Ctrl+H].
+
+== Product-specific actions
+
+The products contained in Helgobox provide additional actions:
+
+- xref:realearn::reaper-actions.adoc[ReaLearn actions]
+- xref:playtime::reaper-actions.adoc[Playtime actions]