Fix golangci-lint by building from source with Go 1.25

Use install-mode: goinstall to build golangci-lint from source with Go 1.25
instead of downloading a prebuilt binary built with Go 1.24.

Changes:
- Add install-mode: goinstall to golangci-lint-action
  - Forces local build with Go 1.25
  - Resolves "Go language version is lower than targeted Go version" error
- Use Go 1.25 for both golangci and gomod jobs
- Add check-latest: true to ensure latest Go patch version
- Add --timeout=5m for golangci-lint
- Remove deprecated id: go field
- Improve formatting and consistency

This is the proper long-term solution, not a workaround.

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

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

Author: kwent

.github/workflows/lint.yml

@@ -10,29 +10,37 @@ jobs:
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v4
-      - name: Set up Go 1.x
+
+      - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.24'
-        id: go
+          go-version: '1.25'
+          check-latest: true
+
       - name: Run Golangci Linter
         uses: golangci/golangci-lint-action@v6
         with:
           version: latest
+          install-mode: goinstall
+          args: --timeout=5m
+
   gomod:
     runs-on: ubuntu-latest
     steps:
-      - name: Set up Go 1.x
+      - name: Set up Go
         uses: actions/setup-go@v5
         with:
           go-version: '1.25'
-        id: go
+          check-latest: true
+
       - name: Checkout Repository
         uses: actions/checkout@v4
+
       - run: |
           go mod tidy
           git diff --exit-code go.mod
           git diff --exit-code go.sum
+
   hadolint:
     runs-on: ubuntu-latest
     steps:
@@ -41,6 +49,7 @@ jobs:
         uses: brpaz/hadolint-action@master
         with:
           dockerfile: 'Dockerfile'
+
   goreleaser:
     runs-on: ubuntu-latest
     steps: