~anthropic/claude-sonnet-latest → B (20:80)

Side B is a small, surgical commit: it adds a real bugfix (room garden pages no longer silently fall back to the public scope when a private room has no content, preventing content leakage), factors out a well-documented `thread_post_index_chronological` helper to eliminate duplicated fragile lookup logic across rpc.rs/garden.rs/ingest.rs, and backs the fix with new integration and browser regression tests. Side A is a sprawling 'reshuffle' commit that mostly moves large chunks of working code into a `legacy/` directory, checks in a huge generated Cargo.lock, and stands up a mostly-empty demo scaffold (health check, counter bump) — it's a project reset with high line count but little durable engineering value per line, and it discards more functionality than it adds.