Add 5 board management tools extending the Trello client:
- trello_create_board — create a new board
- trello_rename_board — rename an existing board
- trello_archive_board — close/archive a board
- trello_open_board — re-open a closed board
- trello_board_details — view board with lists and members
Includes board name-to-ID resolution, 16 new tests, and spec doc.
Issue: #2
