fix: update Go version to 1.26.1 in multiple workflow files for consistency and security improvements

.github/workflows/benchmark.yml

@@ -37,7 +37,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6
         with:
-          go-version: ${{ env.GO_VERSION }}
+          go-version: "1.26.1"
+
           cache-dependency-path: backend/go.sum
 
       - name: Run Benchmark

.github/workflows/codecov-upload.yml

@@ -47,7 +47,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6
         with:
-          go-version: ${{ env.GO_VERSION }}
+          go-version: "1.26.1"
+
           cache-dependency-path: backend/go.sum
 
       # SECURITY: Keep pull_request (not pull_request_target) for secret-bearing backend tests.

.github/workflows/e2e-tests-split.yml

@@ -144,7 +144,8 @@ jobs:
         if: steps.resolve-image.outputs.image_source == 'build'
         uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6
         with:
-          go-version: ${{ env.GO_VERSION }}
+          go-version: "1.26.1"
+
           cache: true
           cache-dependency-path: backend/go.sum
 

.github/workflows/quality-checks.yml

@@ -33,7 +33,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6.3.0
         with:
-          go-version: ${{ env.GO_VERSION }}
+          go-version: "1.26.1"
+
           cache-dependency-path: backend/go.sum
 
       - name: Run auth protection contract tests
@@ -139,7 +140,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6.3.0
         with:
-          go-version: ${{ env.GO_VERSION }}
+          go-version: "1.26.1"
+
           cache-dependency-path: backend/go.sum
 
       - name: Repo health check

.github/workflows/release-goreleaser.yml

@@ -47,7 +47,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6
         with:
-          go-version: ${{ env.GO_VERSION }}
+          go-version: "1.26.1"
+
           cache-dependency-path: backend/go.sum
 
       - name: Set up Node.js