Usage check on prompt

Reports current Claude usage as a compact one-line status by calling the get_claude_usage MCP tool. Fires once at session start by default, and on request when the user asks how much usage is left, what their session or weekly usage is, or whether they are near a limit; optionally at one meaningful seam in a long session. Output format: [Usage: session X% (resets in Yh Zm), weekly W% (resets Sat 1AM)]. Handles the no_token and auth_expired cases by surfacing a one-line claude update needed note instead of failing, and stays silent if the get_claude_usage tool is not registered in this environment. The user can opt out for the session by saying stop reporting usage. Read-o…