docs: narrow the push-exemption guarantee, unbreak two static gates

cancel-in-progress is evaluated against the newly triggered run, so
exempting push means one master merge does not cancel the drill still
running from the previous one — not that a drill always finishes. A
benchmark dispatched on master shares the group and does cancel a
mid-flight drill. Record that bound in the runbook and drop the
overstated wording from the workflow comment and the spec name.

Also repair two gates that fail on master and block every pull request:
the telemetry note referenced an SDK proposal deleted in 408721954a,
and the ui-settings-general README pair carried stale recorded hashes
after both sides were updated together in aa1ec02bc6.

.github/workflows/ci.yml

@@ -23,9 +23,9 @@ on:
 # Negated rather than `== 'pull_request'` so workflow_dispatch keeps cancelling:
 # a re-dispatched runner benchmark holds up to 12 larger runners for 15 minutes
 # and shares this group with the drills on master, so queueing it would delay
-# them. This does not promise every push run finishes (a newer pending run still
-# displaces an older one) — only that the lanes periodically reach a verdict.
-# Rationale and the bound on this carve-out:
+# them. The guarantee is narrow — evaluated against the newly triggered run, so a
+# dispatch on master still cancels a mid-flight drill, and a newer pending push
+# displaces an older one. Bounds and rationale:
 # .agents/notes/implemented/process/2026-07-26-ci-failover-runbook.md
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}