Merge master and correct local acceleration reporting

Reject failed Whisper GPU attempts, identify Llama devices from model buffers, and keep historical diagnostics independent of current settings. Report loaded backends without inferring build support, with regression coverage for each case.

tests/support.py

@@ -112,6 +112,10 @@ class DikteTest(unittest.TestCase):
         i18n.set_language("en")
         self.addCleanup(i18n.set_language, "en")
 
+        # Read once and kept for the life of the process, which across a test
+        # run means one test's machine answering for the next one's.
+        self.patch_attr(ggml, "_MEMORY", None)
+
         # cli.launch_gui replaces this process with the application when no
         # instance is running. A test that reaches it would take the whole run
         # with it and hang, so it fails loudly here instead.