Recover missing desktop Relay provider without restarting Orca

An authenticated desktop can report `relay_provider_unavailable` / `provider_missing` when generating an automatic mobile pairing offer. Account “Connected” reflects the saved account session, not Relay readiness.

Desktop Relay initialization currently runs once. If no service is installed, successful auth mutations only optional-chain the absent service, and the pairing error hides Retry. Restarting reruns initialization, but the screen only offers LAN and diagnostics.

Make missing-provider initialization retryable after sign-in and before automatic pairing, reuse an existing service, and expose Retry Relay with restart/LAN guidance. Preserve startup readiness, shutdown fencing, and LAN independence; avoid adding polling or a second network retry mechanism.

The original production initialization trigger remains unproven. This tracks the confirmed recovery gap, not a cloud outage.

Start by locating the desktop Relay initialization entry point, successful auth mutations, automatic mobile pairing flow, and the pairing error screen. Trace how a missing provider is reported and how restart currently restores it. Done means retry can initialize or reuse Relay after sign-in and before pairing, with restart/LAN guidance while preserving startup readiness, shutdown fencing, and LAN independence.

Written by the indexing model from the issue text.