Mirrors the DB column added in the prior migration. App-level default
is 'standalone' so existing callers of ScriptBuilderSession(...) work
without code changes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
team_id is kept in all three tables — drop deferred until app code
is fully migrated off team_id references.
Tables: script_builder_sessions, script_templates, script_generations
Backfill: user_id/created_by → users.account_id
Co-Authored-By: Claude Sonnet 4.6 <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>
