v6.4.0-beta.10

Features

• Composition: Add expanded option to Refs (#14345)
• Core: Add Story Index error handling (#16319)

Bug Fixes

• Core: Fix paths to be relative to working dir in v7 mode (#16328)
• Core: Don't fetch stories.json, JSON or SSE, if we don't need it (#16318)

Maintenance

• CLI: Add js extension to lit-html imports (#16244)
• Story-sort: Catch errors and direct user towards migration docs (#16242)