Add Telegram interactive visibility controls

Introduce Telegram notification helpers and callback handling to support inline visibility buttons and editable notifications. Added functions to format/truncate memo content, build/parse callback data, construct inline reply_markup (visibility options + open memo URL), and map visibility labels. Implemented handlers to answer callback queries, edit sent messages, fetch memo data, and update memo visibility in the DB. Integrated callback handling into the Telegram webhook flow and send updated notifications when memos are created/changed. Also updated dist build artifacts (including README timestamp) to reflect the changes.

Author: jkjoy

backend/dist/README.md

@@ -1 +1 @@
-This folder contains the built output assets for the worker "memos-api" generated at 2026-04-08T03:43:48.437Z.
+This folder contains the built output assets for the worker "memos-api" generated at 2026-04-08T07:17:37.001Z.