Poll a reconciliation

Fetches reconciliation status and, once finished, the result. status is one of queued, processing, completed, failed. The result object is present only when status is completed; the error object only when status is failed. A reconciliation that ran but could not be balance-verified is intended, documented behaviour, not an error: it still completes with status: completed, result.summary.verified: false, result.verification.is_verified: false with a human-readable result.verification.reason, and credits_charged: 0 (top-level and inside result) — nothing is billed. A verified run carries credits_charged: <n> (n = bank rows). Always branch on verification.is_verified / credits_charged, never on status alone. Visible only to the owning user; requires scope reconcileiq:read OR being the exact key that created it. Non-owned or unknown ids return 404 (no existence leak).