refactor: add markdown frontend

src/beaver_gateway/frontends/markdown/__init__.py

@@ -0,0 +1,15 @@
+"""Markdown frontend — turn-by-turn chat archive backed by ``.md`` files.
+
+The user maintains chats as plain markdown files in an Obsidian vault.
+A plugin in Obsidian POSTs ``{filename, content?}`` to ``/chat`` and the
+frontend parses the file, finds the last turn, and runs the agent if
+the last turn is ``user``. The full response is appended back to the
+file as an ``### Assistant:`` turn. With ``log_all_chats=True`` the
+frontend also subscribes to every other frontend's turns and writes
+them into ``{vault_path}/{logged_subdir}/`` so the vault is the single
+chronological archive of all conversations.
+"""
+
+from beaver_gateway.frontends.markdown.frontend import MarkdownFrontend
+
+__all__ = ["MarkdownFrontend"]