Enhancement: render document notes as markdown (#14626)

---------

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/documents/tests/test_api_documents.py

@@ -3689,6 +3689,7 @@ class TestDocumentApi(DirectoriesMixin, ConsumeTaskMixin, APITestCase):
             {
                 "id": note.id,
                 "note": note.note,
+                "format": Note.Format.PLAIN,
                 "user": {
                     "id": note.user.id,
                     "username": note.user.username,
@@ -3737,11 +3738,64 @@ class TestDocumentApi(DirectoriesMixin, ConsumeTaskMixin, APITestCase):
         resp_data = resp_data[0]
 
         self.assertEqual(resp_data["note"], "this is a posted note")
+        self.assertEqual(resp_data["format"], Note.Format.PLAIN)
 
         doc = Document.objects.get(pk=doc.pk)
         # modified was updated to today
         self.assertEqual(doc.modified.day, timezone.now().day)
 
+    def test_create_markdown_note(self) -> None:
+        doc = DocumentFactory(
+            title="test",
+            content="this is a document which will have a markdown note",
+        )
+
+        response = self.client.post(
+            f"/api/documents/{doc.pk}/notes/",
+            data={"note": "**markdown**", "format": Note.Format.MARKDOWN},
+            format="json",
+        )
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        note = Note.objects.get(document=doc)
+        self.assertEqual(note.format, Note.Format.MARKDOWN)
+
+        response = self.client.get(f"/api/documents/{doc.pk}/notes/", format="json")
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(response.json()[0]["format"], Note.Format.MARKDOWN)
+
+    def test_create_note_rejects_unsupported_format(self) -> None:
+        doc = DocumentFactory(
+            title="test",
+            content="this is a document which will have a note",
+        )
+
+        response = self.client.post(
+            f"/api/documents/{doc.pk}/notes/",
+            data={"note": "unsupported", "format": "html"},
+            format="json",
+        )
+
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn("format", response.json())
+        self.assertFalse(Note.objects.filter(document=doc).exists())
+
+    def test_create_note_requires_note(self) -> None:
+        doc = DocumentFactory(
+            title="test",
+            content="this is a document which will have a note",
+        )
+
+        response = self.client.post(
+            f"/api/documents/{doc.pk}/notes/",
+            data={"format": Note.Format.MARKDOWN},
+            format="json",
+        )
+
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn("note", response.json())
+        self.assertFalse(Note.objects.filter(document=doc).exists())
+
     def test_create_note_only_saves_document_modified_field(self) -> None:
         """
         GIVEN: