docs(ci): describe the desktop CI runner, not gitdan-ci

Comment and doc wording only, from the non-blocking findings on daniel/gitdan#114.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MfBCVP2GbKqXSmmJXRPnXP

README.md

@@ -719,7 +719,7 @@ its bare default; either restores the bug.
 run.** Gitea populates no `changes` field for a title-or-body edit, unlike
 GitHub, so the workflow cannot tell the edit that un-drafts a PR from an
 ordinary body PATCH — a closing-reference fix-up, say. The price is around
-**90 seconds** of a runner shared across four repos on two capacity slots: the
+**90 seconds** of a runner shared across several repos (one capacity-1 `desktop` slot now; measured on gitdan-ci's two): the
 last twelve non-skipped runs of this job, `started_at` to `completed_at` off
 the Actions API, are 83 s median over 77–106 s. `timeout-minutes: 20` is a
 ceiling for a hung suite, not a duration. It is also bounded: the workflow's