ci(cache): Migrate Rust cache to runner-managed multi-level Redis and S3

Centralize cache service management in the Gitea runner for improved persistence and reliability using an SSD-backed S3 backend. This ensures robust verification of multi-tier cache operations.

ci/build-rust.sh

@@ -2,11 +2,14 @@
 set -eu
 
 : "${SCCACHE_REDIS_ENDPOINT:?Set the persistent sccache Redis endpoint}"
+: "${SCCACHE_ENDPOINT:?Set the persistent sccache S3 endpoint}"
+: "${AWS_ACCESS_KEY_ID:?Supply the S3 access key through a BuildKit secret}"
+: "${AWS_SECRET_ACCESS_KEY:?Supply the S3 secret key through a BuildKit secret}"
 : "${JOBS:=8}"
 case "$JOBS" in ''|*[!0-9]*|0) echo 'JOBS must be a positive integer' >&2; exit 1 ;; esac
 
 sccache --start-server
-trap 'sccache --show-stats; sccache --stop-server' EXIT
+trap 'sccache-stats; sccache --stop-server' EXIT
 sccache --zero-stats
 # Bootstrap/Ninja does not inherit Make's job count. Bound both explicitly.
 make package/rust/host/compile -j"$JOBS" RUST_BUILD_JOBS="$JOBS" || \