feat: update Go to 1.25.6

Via tools/toolchain.

Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>

Author: smira

Pkgfile

@@ -3,9 +3,9 @@
 format: v1alpha2
 
 vars:
-  TOOLCHAIN_MUSL_IMAGE: ghcr.io/siderolabs/toolchain-musl:v1.13.0-alpha.0-2-g0823283
+  TOOLCHAIN_MUSL_IMAGE: ghcr.io/siderolabs/toolchain-musl:v1.13.0-alpha.0-3-g3a527b1
   TOOLS_PREFIX: ghcr.io/siderolabs/
-  TOOLS_REV: v1.13.0-alpha.0-6-g896f8b9
+  TOOLS_REV: v1.13.0-alpha.0-8-g98c699e
 
   # renovate: datasource=github-releases depName=containernetworking/plugins
   cni_version: v1.9.0