docs: make the Orbit API and CLI pages match the code

What does this MR do and why?

Several Orbit user pages gave the wrong token scopes, permissions, and error messages for the GitLab API and the CLI. This MR makes them match main and GitLab master. The admin API step in self-managed setup did not say that it needs an administrator token with the api scope.

Related Issues

Relates to #263

Related to https://gitlab.com/gitlab-org/gitlab/-/work_items/633612

The GitLab REST API page gets the same fixes in gitlab-org/gitlab!265619 (merged).

The GitLab MR that removes the REST schema, schema/format, status, and query/templates routes is merged, so the schema page no longer lists the REST schema route.

Testing

We ran the API claims against a GDK on GitLab master 8d9b0e19cc58 with Orbit main 9f4fd5fe. That run had 40 REST and GraphQL checks, the doc query examples, the admin token scope, and the rate limit. We checked the CLI claims against the main source. Vale reports 0 errors. After review, we checked the status, rate limit, and Query.orbit claims again against GitLab master 7575d076e56 and 19-5-stable-ee.

Page	Fix
Self-managed setup	The admin API needs an administrator token with the api scope and takes a top-level group. A subgroup returns 400.
Security	Admin Mode rule, the scopes for REST, MCP, and GraphQL, and the Global Search permission for remote grep.
CLI and troubleshooting	Exit code messages match the CLI, with each not found message and the exit 4 message from glab orbit status. The indexing view takes any of the three scope options. Links go to the REST and GraphQL reference.
Queries, schema	GitLab Orbit API has no Beta note, because it is generally available. Query.orbit is an experiment and needs GitLab 19.6. GraphQL schema link, and "OpenCypher-like".
MCP endpoint	The OAuth scopes that the endpoint accepts, and the query_graph rate limit, which is a default that API requests share.

Performance Analysis

• This merge request does not introduce any performance regression. If a performance regression is expected, explain why.

Agent context: long-form analysis, file-by-file walkthroughs, profiler output, alternatives considered

The pages describe main before the REST endpoint removals in #263. The MRs that remove schema, status, and the other routes also update the pages that name them.

The live checks and their results are in the AI session below.