BREAKING CHANGE(SmartAcme): Refactor challenge handling by removing legacy setChallenge/removeChallenge in favor of pluggable challengeHandlers and update documentation and tests accordingly

ts/handlers/index.ts

@@ -0,0 +1,4 @@
+export type { IChallengeHandler } from './IChallengeHandler.js';
+// Removed legacy handler adapter
+export { Dns01Handler } from './Dns01Handler.js';
+export { Http01Handler } from './Http01Handler.js';