v0.1.16

Patch release for concurrent Notes delete/backspace sync.\n\n- Fixes CRDT hydration for legacy plain-text server snapshots so Backspace/Delete updates can remove existing text instead of being pulled back to old content.\n- Guards remote document refresh after network awaits so in-flight local edits are not overwritten.\n- Adds a desktop/mobile delete convergence stress test and updates existing stress selectors.\n\nValidation: CRDT tests, Notes check, backend tests, suite build, notes build, delete/concurrency/rich stress tests, Android APK build/sign/verify, Docker linux/amd64 build.