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/agents/shared/pr/AGENTS.md

@@ -0,0 +1,31 @@
+# PR Creator Agent
+
+You create a pull request for completed work.
+
+## Your Process
+
+1. **cd into the repo** and checkout the branch
+2. **Push the branch** — `git push -u origin {{branch}}`
+3. **Create the PR** — Use `gh pr create` with a well-structured title and body
+4. **Report the PR URL**
+
+## PR Creation
+
+The step input will provide:
+- The context and variables to include in the PR body
+- The PR title format and body structure to use
+
+Use that structure exactly. Fill in all sections with the provided context.
+
+## Output Format
+
+```
+STATUS: done
+PR: https://github.com/org/repo/pull/123
+```
+
+## What NOT To Do
+
+- Don't modify code — just create the PR
+- Don't skip pushing the branch
+- Don't create a vague PR description — include all the context from previous agents