feat(viz): update trajectory loaders to discover claude-transcript_*.jsonl files

[coderabbitai]

Summary

The Claude plugin stop hook added in #229 saves raw Claude session transcripts as claude-transcript_<session_id>.jsonl under .evolve/trajectories/. However, the current trajectory viz loaders in altk_evolve/viz/data.py only read *.json files and expect single-object JSON, so these .jsonl files are not surfaced in /api/trajectories.

What needs to be done

Update altk_evolve/viz/data.py (and any related loaders / API endpoints) to:

1. Discover claude-transcript_*.jsonl files in the trajectories directory.
2. Parse the JSONL format (one JSON object per line) correctly.
3. Expose them through the /api/trajectories endpoint so they appear in the UI.

Context

• Flagged in PR feat(claude-plugin): add stop hook to save session transcript #229 review: feat(claude-plugin): add stop hook to save session transcript #229 (comment)
• Requested by @vinodmut to track as a follow-up item.