fix(ov_dream): accept a message whose content is a plain string (#4221)

[ntdat812]

Fixes #4221.

Reproduced

One session file, two messages — a block list and a plain string:

AttributeError: 'str' object has no attribute 'get'

parse_messages() iterates message["content"] as a block list. A string iterates into characters, and "p".get("type") raises. The raise leaves parse_messages() before anything is committed, so the failure is not "that message is skipped" — it is "no session in the workspace is ever synced". The reporter measured 91 string bodies in 1609 real messages (5.7%).

The fix

The body is flattened through a small helper: a string is text, a list keeps the existing block handling, and blocks that are not dicts are skipped rather than raising the same way. Nothing else about the parse changes — whitespace-only and empty bodies are still dropped, and non-text blocks are still ignored.

Tests

examples/skills/ov_dream/tests/test_dream_message_content.py — 5 tests through the real parse_messages() with real session files on disk.

Against main with only scripts/dream.py reverted:

FAILED test_string_content_is_parsed_as_text
FAILED test_one_string_message_no_longer_drops_the_others
FAILED test_empty_and_unusable_bodies_are_skipped
FAILED test_message_text_helper_directly
4 failed, 1 passed

The one that passes on both is test_block_lists_still_behave_the_same, which pins the behaviour that must not change. test_one_string_message_no_longer_drops_the_others is the one that matters most: it asserts the messages after the string body still arrive, which is the difference between "one message lost" and "the run aborted".

With the fix: examples/skills/ov_dream/tests/ — 15 passed (10 pre-existing + 5 new). ruff check and ruff format --check clean.

Not changed

A single bad session still aborts the whole dream run, because sync_active_session() has no per-session error boundary. That is a wider behavioural decision than this bug needs, so I left it alone — happy to follow up if you want one session's failure to stop being everyone's.