- Fix FFI panics with catch_unwind and safe CString construction
- Handle poisoned mutex/RwLock after prior panics instead of crashing
- Fix empty block list panics in clear_blocks and invalidate_block
- Reuse Tokio runtime across block fetch batches to reduce overhead
- Add fetch_blocks_with_runtime for caller-managed runtime lifecycle
- Update branding, dependencies, and checkpoints for DragonX
