Import upstream Diehard4 by obscurant

Verbatim contents of the upstream GitHub archive (Diehard4-master.zip,
commit 254ee204deebc64793123a9643c85b7d113c6c22, files dated 2019-05-21).

Imported unmodified so that every change in this fork is visible as a diff
against the original, which is what GPL-3.0 section 5(a) is asking for.
All code in this commit is obscurant's work, not mine.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

cinnamon/theme.json

@@ -0,0 +1,10 @@
+{ 
+   "cinnamon-theme": {
+   "name": "Diehard4", 
+   "author": "zomby", 
+   "version": "1.0",
+   "type":   "custom",
+   "thumbnail": "thumbnail.png", 
+   "url": "http://zomby.deviantart.com" 
+    }
+}