Fix golangci-lint compatibility by using Go 1.24 for lint job

- Use Go 1.24 specifically for golangci-lint job (temporary workaround)
  - golangci-lint is currently built with Go 1.24
  - Avoids "Go language version is lower than targeted Go version" error
- Keep Go 1.25 for gomod validation job (actual project version)
- Update actions/setup-go from v4 to v5
- Remove unnecessary GO111MODULE environment variable
- Use quoted version strings for consistency

This is a temporary workaround until golangci-lint releases a version
built with Go 1.25. Build, test, and release jobs continue to use Go 1.25.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: kwent

.github/workflows/lint.yml

@@ -11,11 +11,9 @@ jobs:
       - name: Checkout Repository
         uses: actions/checkout@v4
       - name: Set up Go 1.x
-        uses: actions/setup-go@v4
-        env:
-          GO111MODULE: off
+        uses: actions/setup-go@v5
         with:
-          go-version: 1.25
+          go-version: '1.24'
         id: go
       - name: Run Golangci Linter
         uses: golangci/golangci-lint-action@v6
@@ -25,11 +23,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Set up Go 1.x
-        uses: actions/setup-go@v4
-        env:
-          GO111MODULE: off
+        uses: actions/setup-go@v5
         with:
-          go-version: 1.25
+          go-version: '1.25'
         id: go
       - name: Checkout Repository
         uses: actions/checkout@v4