fix: convert antfarm from broken submodule to regular directory

Fixes Gitea 500 error caused by invalid submodule reference.
Converted antfarm from pseudo-submodule (missing .gitmodules) to
regular directory with all source files.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

antfarm/vercel.json

@@ -0,0 +1,3 @@
+{
+  "outputDirectory": "landing"
+}