Follow the seal bet in the Likely-source line

A standalone-tag file showed 'platform not specified' while the panel
below priced the Muse Content Seal removal - the platform line lagged
the attribution the seal signal and the strength router already make.
The fallback now attributes 'Meta Muse Image (attributed by the
standalone AI digital-source tag)' when no more specific attribution
applies, so the source line and the priced target agree. Apple Photos
Clean Up keeps its own attribution; the hedge names the attribution
basis, not a detection.

tests/test_identify.py

@@ -690,6 +690,27 @@ class TestIdentifyRealSamples:
         assert "Invisible Content Seal watermark (Meta Muse attribution)" in r.watermarks
         assert any("meta.ai/identification" in c for c in r.caveats)
 
+    def test_seal_platform_attribution_follows_the_signal(self, tmp_path: Path):
+        """The Likely-source line follows the same bet the seal signal makes.
+
+        Apple keeps its own attribution; every other standalone-tag file gets the
+        hedged Muse attribution instead of "platform not specified", so the panel
+        that prices the Content Seal and the source line agree.
+        """
+        muse = tmp_path / "muse.jpg"
+        muse.write_bytes(
+            b'\xff\xd8\xff\xe1<x:xmpmeta Iptc4xmpExt:DigitalSourceType="trainedAlgorithmicMedia"></x:xmpmeta>\xff\xd9'
+        )
+        apple = tmp_path / "apple.jpg"
+        apple.write_bytes(
+            b'\xff\xd8\xff\xe1<x:xmpmeta Iptc4xmpExt:DigitalSourceType="compositeWithTrainedAlgorithmicMedia" photoshop:Credit="Apple Photos Clean Up"></x:xmpmeta>\xff\xd9'
+        )
+
+        assert identify(muse, check_visible=False, check_invisible=False).platform == (
+            "Meta Muse Image (attributed by the standalone AI digital-source tag)"
+        )
+        assert identify(apple, check_visible=False, check_invisible=False).platform == "Apple Photos (Clean Up AI edit)"
+
     def test_c2pa_backed_file_gets_no_content_seal_attribution(self):
         """C2PA issuers win first: a manifest-backed file is not Meta-routed."""
         r = identify(SAMPLES_DIR / "flux-1.png", check_visible=False, check_invisible=False)