chore: switch license from GPL-v3 to Apache-2.0

docs: reorganize project specs and clean up public-facing docs

fix(markdown): resolve tree-sitter captures iteration

feat(markdown): render tree-sitter highlight runs

feat(markdown): add tree-sitter highlight spans

feat(editor): add mouse drag selection

docs(spec): add Phase 1.2 highlighting steps

docs(plan): mark Phase 1.1 complete

feat(editor): wire text input and key actions

feat(ui): render editor view with caret placeholder

feat(editor): add buffer+cursor core with tests

docs(spec): add Phase 1 core editor plan

fix: import AppContext for cx.new

fix(macos): pin core-text to avoid core-graphics split

docs: add cargo run troubleshooting