fix(e2e): skip chat history tests when read-only notebook has no turns (#155)

The read-only test notebook may have a conversation ID but no actual
chat turns, causing IndexError on empty turns_data. Skip gracefully
with a descriptive message instead of crashing.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

tests/e2e/test_chat.py

@@ -197,6 +197,11 @@ class TestChatHistoryE2E:
         )
 
         assert turns_data is not None
+        if not turns_data:
+            pytest.skip(
+                "Read-only notebook has a conversation but no chat turns — "
+                "cannot verify turn structure. Seed the notebook with chat messages to enable this test."
+            )
         assert isinstance(turns_data[0], list)
         turns = turns_data[0]
         assert len(turns) >= 1
@@ -219,6 +224,11 @@ class TestChatHistoryE2E:
         )
 
         assert turns_data is not None
+        if not turns_data:
+            pytest.skip(
+                "Read-only notebook has a conversation but no chat turns — "
+                "cannot verify question text. Seed the notebook with chat messages to enable this test."
+            )
         turns = turns_data[0]
         question_turns = [t for t in turns if isinstance(t, list) and len(t) > 3 and t[2] == 1]
         assert question_turns, "No question turn found in response"
@@ -240,6 +250,11 @@ class TestChatHistoryE2E:
         )
 
         assert turns_data is not None
+        if not turns_data:
+            pytest.skip(
+                "Read-only notebook has a conversation but no chat turns — "
+                "cannot verify answer text. Seed the notebook with chat messages to enable this test."
+            )
         turns = turns_data[0]
         answer_turns = [t for t in turns if isinstance(t, list) and len(t) > 4 and t[2] == 2]
         assert answer_turns, "No answer turn found in response"