- Cache key: replace run_id (unique per build) with date-based key
so entries are reused within the same day and rotate daily
- Skip cache save on exact hit (act_runner can't overwrite keys)
- build.sh: set CCACHE_DIR/CCACHE_BASEDIR inside rattler-build's
isolated env so release builds actually use the cached directory
- build.sh: print ccache stats at end for diagnostics
- Add disk space cleanup step to build.yml (matching release.yml)
- Remove cross-build cache fallback in release.yml (different -O flags)
- Add runner cleanup daemon (.gitea/runner/) with systemd timer
to purge stale cache entries, Docker data, and old workspaces