docs: record gosec cache restoration

CHANGELOG.md

@@ -38,7 +38,7 @@ A `### Breaking` section is used in addition to Keep a Changelog's standard sect
 - Fixed `decorate-pr/action.yml` YAML validation by extracting PR comment rendering into `decorate-pr/build-comment.sh`, removing the duplicated changelog extraction step, and correcting the gate failure output reference.
 - Fixed docs-only detection in `decorate-pr` changelog gate: file list was iterated in a piped subshell so `docs_only` never propagated to the parent scope; replaced pipe with process substitution.
 - Pinned `securego/gosec` and `golang/govulncheck-action` to concrete version tags (`v2.22.4` and `v1.0.4`) so self-hosted Gitea runners can resolve them via direct git clone without relying on the GitHub Actions floating-tag API.
-- Added `GOTOOLCHAIN: auto` environment variable to `gosec` and `govulncheck-action` steps in `push-validation` and `prepare-release` workflows to prevent Go toolchain version mismatches inside the act runner container.
+- Restored explicit gosec caching by storing a pinned `v2.22.4` binary under `${{ runner.temp }}/gosec-bin` with `actions/cache@v4`, so CI keeps fast security scans while still using the Go 1.26 toolchain from `setup-go`.
 - Replaced `securego/gosec` composite action with a direct `go install github.com/securego/gosec/v2/cmd/gosec@v2.22.4 && gosec ./...` run step so gosec uses the Go 1.26 toolchain installed by `setup-go` rather than the action's bundled Go 1.24 binary which ignores `GOTOOLCHAIN=auto`.
 
 ## [1.0.2] - 2026-03-21