docs: fully align English package with Chinese package

docs: separate quick start from manual install flow

docs: simplify quick start and trim README sections

fix: require explicit language package and vault path during setup

docs: improve README layout and add installation guide

docs: refine teaser messaging and expand homepage content

docs: update teaser image and homepage messaging

refactor: split repository into bilingual packages

chore: add existing scholar-skill files

docs: scaffold bilingual documentation structure