docs(readme): sync zh-CN with changelog

docs(readme): sync with changelog

feat(debug): add runtime toggle for developer messages

merge: terra-natural-generation-fixes into master

fix(terra): relax end chunk validation and improve paste diagnostics

chore(gen): add observability and docs for success-only chunk processing

fix(end): correct end altitude range and y-bound clamping

fix(terra): enforce validateChunkBeforePaste semantics and align scan rules

fix(gen): mark chunk processed only after successful paste

refactor(paste): propagate paste success result through callbacks

refactor(core): centralize chunk processed marker utility

test(core): add chunk processing policy baseline

docs: add terra natural-generation fixes implementation plan

docs: add terra natural-generation compatibility design

docs: add chunk I/O throttling implementation plan