chore: bump Go toolchain to 1.26.3 (#43)

Pin Go version to 1.26.3 across go.mod, CI workflows, and Dockerfiles
for canonical alignment with the rest of the luxfi/* stack.

.github/workflows/build-test.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.26.1'
+          go-version: '1.26.3'
           check-latest: true
       - name: Run static analysis tests
         shell: bash
@@ -32,7 +32,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
-          go-version: '1.26.1'
+          go-version: '1.26.3'
       - run: go test -v -timeout 10m ./...
         env:
           CGO_ENABLED: "0"
@@ -53,7 +53,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.26.1'
+          go-version: '1.26.3'
       - name: Run e2e tests
         shell: bash
         run: scripts/tests.e2e.sh

.github/workflows/release.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.25.5'
+          go-version: '1.26.3'
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v6
         with: