Partially incorporate PR feedback from Alex

- Reference `asm_differ` issue 56
- Add Typescript type for `DiffResponse`
- Make `FormatDiffText` a JSX component
- Handle missing `row.base`/`row.current`

backend/coreapp/asm_diff_wrapper.py

@@ -117,7 +117,8 @@ class AsmDifferWrapper:
 
         display = Display(basedump, mydump, config)
 
-        # TODO: It would be nice to get a python object from `run_diff()` to avoid the JSON roundtrip
+        # TODO: It would be nice to get a python object from `run_diff()` to avoid the
+        # JSON roundtrip. See https://github.com/simonlindholm/asm-differ/issues/56
         result = json.loads(display.run_diff()[0])
         result["error"] = None