Reorganize top-level directories with clearer naming convention

app -> app-desktop-macos, presets -> app-presets, server -> remote-server,
daw-config-reaper -> osc-config-daw, plugin-reaper-realearn -> plugin-reaper-relearn.
Updated run.py and presets.py path references accordingly.

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

plugin-reaper-relearn/doc/playtime/modules/ROOT/pages/usage.adoc

@@ -0,0 +1,19 @@
+= Basic usage
+
+Let's get familiar with the basics!
+
+A typical Playtime usage scenario, from beginning to end, looks like this:
+
+. xref:usage/prepare.adoc[]
+. xref:usage/create.adoc[]
+. xref:usage/play.adoc[]
+. xref:usage/grid-controllers.adoc[]
+. xref:usage/adjust.adoc[]
+. xref:usage/structure.adoc[]
+. xref:usage/arrangement.adoc[]
+. xref:usage/render.adoc[]
+
+In the following sections, we will learn step by step how to do this.
+
+TIP: This guide assumes that you already installed Playtime.
+If not, head to the xref:installation.adoc[] page!