forgetest: image.health matches the kernel by identity, hash aside

The manifest lists the modules directory without the kernel's
LOCALVERSION_AUTO hash (the hash does not reproduce across a re-patch of
the same source, so the image manifest strips it). image.health still
compared the full running release against that list and failed on the
first post-flash run of image 20260902144848 with the kernel
6.12.20-fslc-fslc-g72a0b1431a9d against the manifest's 6.12.20-fslc-fslc.

kernel_ident() strips the same suffix from both sides, so a manifest with
or without the hash matches the running kernel, and a different base
release still fails. tests/test_image.py covers both forms.

Catalog consequence: only image.health's own implementation hash moves;
it is an always-run test, so no inherited result is affected.

forgetest/tests/test_image.py

@@ -0,0 +1,24 @@
+import unittest
+
+from forgetest.suite import image
+
+
+class KernelIdentTests(unittest.TestCase):
+    def test_localversion_hash_is_stripped(self):
+        self.assertEqual(image.kernel_ident("6.12.20-fslc-fslc-g72a0b1431a9d"), "6.12.20-fslc-fslc")
+        self.assertEqual(image.kernel_ident("6.12.20-fslc-fslc+g72a0b1431a9d"), "6.12.20-fslc-fslc")
+
+    def test_plain_name_is_unchanged(self):
+        self.assertEqual(image.kernel_ident("6.12.20-fslc-fslc"), "6.12.20-fslc-fslc")
+        self.assertEqual(image.kernel_ident("6.12.20-fslc-g12"), "6.12.20-fslc-g12")
+
+    def test_release_matches_manifest_with_or_without_hash(self):
+        rel = "6.12.20-fslc-fslc-g72a0b1431a9d"
+        self.assertTrue(image.kernel_matches(rel, ["6.12.20-fslc-fslc"]))
+        self.assertTrue(image.kernel_matches(rel, ["6.12.20-fslc-fslc-gf52af5b522f4"]))
+        self.assertTrue(image.kernel_matches(rel, []))
+        self.assertFalse(image.kernel_matches(rel, ["6.12.19-fslc-fslc"]))
+
+
+if __name__ == "__main__":
+    unittest.main()