Mosaic connected-account OAuth routing and modal follow-ups #10117

Move the connected-account roadmap out of the feature tests in PR #10086.

• Evaluate sharing scope and reconnect helpers with the legacy UI.
• Replace the OAuth redirect hold timeout when routing can signal navigation completion or cancellation. Include whether Mosaic should await navigation.
• Restore the UserProfile modal after OAuth returns. The current mode prop preserves legacy callback URL state. When the Mosaic modal host is available, evaluate a host callback that prepares the redirect URL.

These are product and routing follow-ups. They are separate from the test-only redirect recovery coverage.