Validation note:

This PR fixes a feedback-chain bug in the config reload workflow.

Before this change, the config save/reload route notified the gateway reload path without surfacing reload failures back to the API response. As a result, the frontend displayed a successful save/reload state even when the gateway reload operation failed and the active runtime could still be using the previous config.

This PR changes the workflow in two important ways:

• the server awaits the gateway reload notification and includes a structured reload.gateway result in the API response;
• the frontend distinguishes "config saved" from "gateway reload failed" and surfaces the reload failure to the user.

Validation commands currently listed by this PR:

npm exec -- tsc --noEmit -p tsconfig.json
npm --workspace ui run build

The implementation direction is correct, but the self-validation is still incomplete. A focused regression test should stub getPilotDeckGateway().reloadConfig() to throw and assert that:

• PUT /api/config still returns a config response;
• the response contains reload.gateway.error;
• the frontend hook shows an error instead of the success message.

That test would prove the fixed failure path, not only the type/build correctness.