Move board-metadata and board-lifecycle functions (board_metadata_path,
read/write_board_metadata, _default_board_display_name, _dir_holds_board,
create_board, list_boards, remove_board) out of the kanban_db facade into
the topical sibling hermes_cli/kanban_db_boards.py, offsetting this PR's
facade growth past its main-pinned FILE_LINES cap (moved code keeps its
cap; re-exported from the facade tail so imports/monkeypatching are
unchanged).
Also drop the blind except Exception in the dashboard's _ws_board_live:
read_board_metadata never raises (missing/malformed board.json yields the
synthesized entry), so the archived-tombstone check needs no try/except.
9aaf2fda3c