UR-Nexus 1.58.0

• Added per-agent cost and token attribution: ur agent-inspect --costs.
  stats.ts already read every {sessionId}/subagents/agent-{agentId}.jsonl
  transcript, but only to fold those tokens into a single total, so a fan-out
  that consumed most of a session's budget was indistinguishable from one that
  did not. Rows are attributed by filename rather than by joining turns back to
  the spawning tool_use, because the Agent tool's input carries no agent id
  and any such join would be a guess.
• The breakdown reports tokens and omits the money column on a local runtime.
  calculateUSDCost returns 0 for Ollama, so a cost column would have rendered
  as a wall of $0.00 and read as a broken feature; cost appears only when a
  provider actually billed.