cli: address Bugbot/Copilot review on the cell fan-out layer
Commit

- Bound resolveCellBaseURLs's catalog lookup with cellResolveTimeout, like resolveRepoCellTarget: a hung core must not stall the command before the fan-out even starts.
- Refuse a concrete baseURL without a jurisdiction: minting a home-jurisdiction token and dialing a foreign cell with it is exactly the mismatch resolveRepoCellTarget refuses; such a group stays on home routing.
- Key groupReposByCell on (cell, jurisdiction): blank-cell index rows in different jurisdictions no longer collapse into one group routed by whichever repo came first.
- Single-flight token mints per jurisdiction (mintSlot) instead of one factory-wide mutex held across the exchange: a slow region's mint no longer burns other cells' per-cell deadlines. Failed mints cache nothing, so the next caller retries.
Co-Authored-By: Claude Fable 5 noreply@anthropic.com Entire-Checkpoint: ab23b05bf985
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