chore(cli): drop orbit-local back-compat and reframe README around one Orbit

What does this MR do and why?

The orbit-local → orbit-cli rename is done and the shipped glab pulls the orbit-cli package, so the old orbit-local archives are unused. This stops producing them: release scripts, npm, CI, and installers now ship only orbit-cli artifacts. The README also drops the two-product framing for one Orbit you index and query.

Related Issues

Testing

Release scripts, installers, and docs only. Verified glab main reads the orbit-cli package; the next tag pipeline is the real check.

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

Distribution: build-local-cli.sh, upload-local-cli-release.sh (dropped the legacy package name and the copy + dual upload), publish-npm.sh, and .gitlab/ci/release-local.yml now emit and reference orbit-cli-* archives under the orbit-cli generic package only. install.sh and install.ps1 download from that package. Removed the empty crates/orbit-local/ directory and a stale path in a repo_map doc comment. Corrected skills/orbit/SKILL.md (glab pulls orbit-cli, not orbit-local; skill version 0.30.0 → 0.30.1).

Cross-repo check: gitlab-org/cli main uses package name orbit-cli with orbit-cli-* asset names, and no orbit-local package references remain there. The orbit_local_* config keys (and GLAB_ORBIT_LOCAL_* env vars) are still defined and read by glab, so they are left unchanged.

README: the two run sections and access tables collapse into one; quickstarts become "index a local repository" and "query the hosted graph"; the Features table uses local/hosted graph columns; the runtime split stays only in Architecture. The docs/ tree is untouched for the separate docs rewrite.