fix: add __main__.py so python -m directdnsonly works in container 🐛

- directdnsonly/__main__.py: inserts package dir into sys.path before
  importing main.py (which uses short-form relative imports) then calls
  main(); works for both `python -m directdnsonly` and the dadns script
- pyproject.toml: wire up `dadns` console script entry point

directdnsonly/__main__.py

@@ -0,0 +1,17 @@
+import os
+import sys
+
+
+def run():
+    # main.py uses short-form imports (from app.*, from worker) that resolve
+    # relative to the directdnsonly/ package directory. Insert it into the
+    # path before importing so `python -m directdnsonly` and the `dadns`
+    # console script both work without changing main.py.
+    sys.path.insert(0, os.path.dirname(__file__))
+    from main import main
+
+    main()
+
+
+if __name__ == "__main__":
+    run()

pyproject.toml

@@ -20,6 +20,9 @@ dependencies = [
     "requests (>=2.32.0,<3.0.0)",
 ]
 
+[project.scripts]
+dadns = "directdnsonly.__main__:run"
+
 [tool.poetry]
 package-mode = true