fix: reload legacy session rows

[chethanuk]

Summary

• normalize datetime created_at values when serializing messages
• tolerate legacy session rows that only stored content and may omit created_at
• add regression coverage for legacy message reload/append behavior

Validation

• uv run pytest tests/unit/test_message.py -v
• uv run pytest tests/unit/test_message.py -k "legacy_content_only or legacy_message_can_be_reloaded_and_extended or to_dict_timestamp_format" -v
• uv run ruff check openviking/message/message.py tests/unit/test_message.py

[github-actions]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis 🔶 1358 - Partially compliant Compliant requirements: Handle legacy session rows with only 'content' field Tolerate missing 'created_at' in legacy rows Normalize datetime 'created_at' values when serializing Non-compliant requirements: Fix RuntimeError: not found when appending to session messages file (requires integration testing to verify) Requires further human verification: Fix RuntimeError: not found when appending to session messages file

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🏅 Score: 90

🧪 PR contains tests

🔒 No security concerns identified

✅ No TODO sections

🔀 No multiple PR themes

⚡ No major issues detected

[github-actions]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Handle naive datetime objects safely Add handling for naive datetime objects (without timezone info) to prevent astimezone() errors. Assume naive datetimes are in UTC and explicitly set their timezone before conversion. openviking/message/message.py [66-72] created_at_val = self.created_at or datetime.now(timezone.utc).isoformat() if isinstance(created_at_val, datetime): + if created_at_val.tzinfo is None: + # Naive datetime, assume UTC + created_at_val = created_at_val.replace(tzinfo=timezone.utc) created_at_val = ( created_at_val.astimezone(timezone.utc) .isoformat(timespec="milliseconds") .replace("+00:00", "Z") ) Suggestion importance[1-10]: 6 __ Why: The suggestion correctly identifies a potential issue with naive datetime objects (without timezone info) that could cause astimezone() to fail. Adding this check improves robustness, and the change is accurate within the PR's context.	Low