Move every rule both runtimes applied into core/ (tokenling-core): the prompt contract, stop and context-fit rules, the lookup line loop and text filters, the body, care and offers, tag effects, the day log and diary, turn scheduling and save reading. The host links it natively; core/wasm compiles it to WebAssembly for the page and its brain worker. The browser's local mode now runs the same engine as the host and plays the same effects, replacing web/world.ts, web/app/body.ts and the TypeScript copies of care, tags, turns, diary and save rules, and the host's types.rs, world.rs and its own simulation and turn code. Hosted rows keep their stored layout. Sampling settings travel in the shared request. The module is built by site/build.sh, hashed with the app and kept offline. Checks: npm test (300 parity states through WebAssembly, 13 engine/save tests), 6 core and 17 host Rust tests, native/Python parity plus a 31-step native/WebAssembly engine replay in two time zones, and both browser flows with the real v6 brain and native host. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BmRXrH3X8VnAPbuCgo6PgW