Add GOCACHEPROG binary and pre-build stdlib cache for Go 1.25.5

- Build a new cacheprog binary to enable read-only cache access.
- Pre-build the standard library cache in a dedicated GOCACHE directory.
- Update compile script to use GOCACHEPROG for improved caching during builds.

Author: koki-develop

packages/go/1.25.5/build.sh

@@ -2,3 +2,11 @@
 curl -LO https://go.dev/dl/go1.25.5.linux-amd64.tar.gz
 tar -xzf go1.25.5.linux-amd64.tar.gz
 rm go1.25.5.linux-amd64.tar.gz
+
+# Build GOCACHEPROG binary for read-only cache access
+CGO_ENABLED=0 ./go/bin/go build -o cacheprog cacheprog.go
+
+# Pre-build standard library cache
+export GOCACHE=$PWD/cache
+mkdir -p $GOCACHE
+CGO_ENABLED=0 ./go/bin/go build std

packages/go/1.25.5/compile

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 
 mv $1 $1.go
-GOCACHE=$PWD go build -o binary *.go
+export GOCACHEPROG="/piston/packages/go/1.25.5/cacheprog /piston/packages/go/1.25.5/cache"
+CGO_ENABLED=0 go build -o binary *.go
 chmod +x binary