Archive the marks the new icon replaces

Neither is referenced by the app or the build; branding/archive/README.md
says what each one was and why it did not survive the sizes an app icon
is actually drawn at.

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

branding/archive/README.md

@@ -0,0 +1,11 @@
+# Archive
+
+The marks Triple-C shipped before the current one, kept for reference.
+
+| File | Notes |
+|---|---|
+| `triple-c-app-logo.png` | First mark: orange tile, overlapping C letterforms, "TRIPLE-C / CONTAINERIZED CODING" set inside the icon. |
+| `triple-c-app-logov2.png` | Second mark: orange sunburst with "Triple-C / Coding Container" over it, transparent ground. |
+
+Both were drawn at poster size and carried type inside the icon, so nothing in them survived the
+16–32 px range where an app icon actually lives. Neither is referenced by the app or the build.