chore: reorganize structure

source/html/cut.go

source/html/generate.go

source/html/sync.go

source/main.go

source/template/prepare.go

source/types/page-data.go

source/types/snippets-specification.go

source/types/sync-specification.go

source/util/html.go

source/util/id.go

source/version.go

web/index.html