#6352: fix(ux): update gateway token error message UI location

## Summary Updates error messages to point users to 'Overview → Gateway Access' instead of the old 'Control UI settings' which no longer exists. ## Changes - `src/gateway/server/ws-connection/message-handler.ts`: Updated `uiHint` and `passwordHint` messages - `src/gateway/server.auth.e2e.test.ts`: Updated test assertion - `docs/help/faq.md`: Updated FAQ references - `docs/start/getting-started.md`: Updated getting started guide ## Test plan - [x] Lint passes - [x] Build passes - [x] Test assertion updated to match new message Closes #2032 Supersedes #2063 <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR updates user-facing gateway auth error hints (token/password) to direct users to the new UI location **Overview → Gateway Access** instead of the removed “Control UI settings”. It also updates the corresponding E2E assertion and refreshes two docs pages (FAQ + Getting Started) to reference the new location, keeping guidance consistent with the server error messaging and current dashboard UX. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - Changes are limited to user-facing strings in one server helper, a single test assertion, and corresponding docs updates; no control flow or protocol behavior is altered. - No files require special attention <!-- greptile_other_comments_section --> **Context used:** - Context from `dashboard` - CLAUDE.md ([source](https://app.greptile.com/review/custom-context?memory=fd949e91-5c3a-4ab5-90a1-cbe184fd6ce8)) - Context from `dashboard` - AGENTS.md ([source](https://app.greptile.com/review/custom-context?memory=0d0c8278-ef8e-4d6c-ab21-f5527e322f13)) <!-- /greptile_comment -->