docs(skill): trim the remote orbit skill

What does this MR do and why?

The remote Orbit skill that glab skills install orbit gives coding agents carried about 7,100 words of hand-written prose. Two reference files were copies from the embedded skill, and the setup checklist duplicated the troubleshooting guide. It now weighs 5,600 words with the same guidance in fewer places. The frontmatter description drops from 92 to 43 words.

Related Issues

Relates to #1274

Testing

Every remaining command and flag matches orbit <cmd> --help on 0.121.0. No link points at the two deleted files, and every recipes anchor resolves. The corpus smoke test runs in CI; locally the ClickHouse container never became ready. Skill version 0.27.0.

Performance Analysis

None.

• 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

Part 4 of a 4-MR prompt-trim stack: !2490 (merged) server registries, !2492 (merged) local help text, !2489 (merged) embedded orbit-cli skill.

query_language.md is untouched because it is a generated copy of the docs page. Every em and en dash outside it is gone. Two review agents checked the diff. Their fixes: the iteration budget and reporting sections now defer to their references. The Managed CLI section regained the install/update rule and the glab-owned config keys. The glab version note attributes the flat command form to the Orbit binary, not a glab release.