fix: use jq --arg to pass RULESET_NAME in check-required-status-checks.sh

[kitsuyui]

Problem

In scripts/check-required-status-checks.sh, RULESET_NAME was directly shell-expanded into a jq filter string:

gh api ... | jq -r ".[] | select(.name == \"${RULESET_NAME}\")"

If the ruleset name contains " or \, the jq filter would be syntactically broken or behave incorrectly (jq literal injection).

Fix

Changed to pipe gh api output to jq -r --arg name "${RULESET_NAME}", using jq's --arg option to safely separate data from code:

gh api ... | jq -r --arg name "${RULESET_NAME}" '.[] | select(.name == $name)'

This is the same pattern applied to configure-branch-ruleset.sh in PR #85.

Verification

• shellcheck: pass
• shfmt: pass
• actionlint: pass

Scope

Single-line change in scripts/check-required-status-checks.sh. Functionally equivalent for typical ruleset names; prevents corruption for names containing " or \.