Harden detached worker module startup

src/docforge/_projection_worker_main.py

@@ -0,0 +1,8 @@
+"""Private module entry point for the detached projection worker."""
+
+from __future__ import annotations
+
+from .projection_worker import main
+
+if __name__ == "__main__":
+    raise SystemExit(main())

src/docforge/projection_worker.py

@@ -201,7 +201,7 @@ def _invoke_worker(request: bytes) -> subprocess.CompletedProcess[bytes]:
             "PYTHONUTF8": "1",
         }
     )
-    command = [sys.executable, "-I", "-m", "docforge.projection_worker"]
+    command = [sys.executable, "-I", "-m", "docforge._projection_worker_main"]
     with tempfile.TemporaryFile() as output:
         completed = subprocess.run(
             command,