implemented a lot of features

lib/subject/index.ts

@@ -0,0 +1,5 @@
+/**
+ * Conventions of binary posts (subject lines, file identity), independent of AdonisJS.
+ */
+export { parseSubject, type ParsedSubject } from './parse.js'
+export { fileKey, weakFileKey, looksLikeFilename } from './file_key.js'