Previously save_to_library() hardcoded parameters_schema to empty and
always used session.latest_script. Now accepts optional overrides from
the frontend for parameterized script bodies.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Extract JSONB messages array from script_builder_sessions into a proper
script_builder_messages table with individual columns for role, content,
script, tokens, etc. Migration handles data migration from JSONB to rows.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>