fix: update Go installation scripts to version 1.25.6 and remove obsolete 1.25.5 script

.github/workflows/benchmark.yml

@@ -21,6 +21,7 @@ concurrency:
 
 env:
   GO_VERSION: '1.25.6'
+  GOTOOLCHAIN: auto
 
 # Minimal permissions at workflow level; write permissions granted at job level for push only
 permissions:

.github/workflows/codecov-upload.yml

@@ -14,6 +14,7 @@ concurrency:
 env:
   GO_VERSION: '1.25.6'
   NODE_VERSION: '24.12.0'
+  GOTOOLCHAIN: auto
 
 permissions:
   contents: read

.github/workflows/codeql.yml

@@ -14,6 +14,7 @@ concurrency:
 
 env:
   GO_VERSION: '1.25.6'
+  GOTOOLCHAIN: auto
 
 permissions:
   contents: read

.github/workflows/e2e-tests.yml

@@ -59,7 +59,8 @@ on:
 
 env:
   NODE_VERSION: '20'
-  GO_VERSION: '1.21'
+  GO_VERSION: '1.25.6'
+  GOTOOLCHAIN: auto
   REGISTRY: ghcr.io
   IMAGE_NAME: ${{ github.repository_owner }}/charon
 

.github/workflows/nightly-build.yml

@@ -15,6 +15,9 @@ on:
       default: "false"
 
 env:
+  GO_VERSION: '1.25.6'
+  NODE_VERSION: '24.12.0'
+  GOTOOLCHAIN: auto
   GHCR_REGISTRY: ghcr.io
   DOCKERHUB_REGISTRY: docker.io
   IMAGE_NAME: wikid82/charon

.github/workflows/quality-checks.yml

@@ -17,6 +17,7 @@ permissions:
 env:
   GO_VERSION: '1.25.6'
   NODE_VERSION: '24.12.0'
+  GOTOOLCHAIN: auto
 
 jobs:
   backend-quality:

.github/workflows/release-goreleaser.yml

@@ -12,6 +12,7 @@ concurrency:
 env:
   GO_VERSION: '1.25.6'
   NODE_VERSION: '24.12.0'
+  GOTOOLCHAIN: auto
 
 permissions:
   contents: write