Move old bot versions into src/old

src/ now holds only the running bot (ChargeBilledAutomation.py,
cms1500_text.py) and its build spec. The 7 Apr and 21 Apr versions,
the Document AI trials, their specs and the copied PyInstaller notes
move to src/old/ unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pyproject.toml

@@ -18,5 +18,5 @@ dev = [
 ]
 
 [tool.pytest.ini_options]
-# src/test_docai.py and src/test_pdf.py are old Document AI scripts, not tests
+# src/old/test_docai.py and src/old/test_pdf.py are old Document AI scripts, not tests
 testpaths = ["tests"]