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/realearn/antora.yml

@@ -0,0 +1,10 @@
+name: realearn
+title: ReaLearn Reference
+version: ~
+nav:
+  - modules/ROOT/nav.adoc
+start_page: introduction.adoc
+asciidoc:
+  attributes:
+    # For making menu and button macros work
+    experimental: true