test(ebuild): wave-3 smoke tests for every public module

- tests/ebuild/test_smoke_imports.py: import-smoke every public module
  (parameterized). Closes the ~93% module-coverage gap with a baseline
  that catches AttributeError + circular-import regressions.

Author: EmbeddedOS Fix Bot

tests/ebuild/test_smoke_imports.py

@@ -0,0 +1,28 @@
+"""Smoke tests: import every public ebuild module.
+
+This catches AttributeErrors, circular-import bugs, and refactor breakages
+before they reach production. Each import is independently tested so a
+single broken module does not mask the others.
+"""
+import importlib
+import pkgutil
+
+import pytest
+
+
+PACKAGE = "ebuild"
+
+
+def _all_submodules(package_name: str):
+    pkg = importlib.import_module(package_name)
+    for m in pkgutil.walk_packages(pkg.__path__, prefix=f"{package_name}."):
+        # Skip private + test packages
+        if "._" in m.name or ".tests" in m.name:
+            continue
+        yield m.name
+
+
+@pytest.mark.parametrize("modname", list(_all_submodules(PACKAGE)))
+def test_import(modname):
+    """Every public ebuild module must import cleanly."""
+    importlib.import_module(modname)