Modify linter configuration for copyright header validation

Author: hanzjk

agent-manager-service/.github/linters/.golangci.yaml

@@ -39,6 +39,9 @@ linters:
         - github.com/wso2-enterprise/agent-manager-service/spec\.PostgresQueryStats
     goheader:
       template-path: .github/copyright_header.tmpl
+      values:
+        regexp:
+          YEAR: "\\d{4}"
   exclusions:
     generated: lax
     rules:

agent-manager-service/scripts/lint.sh

@@ -1,3 +1,6 @@
 goimports -w .
 golangci-lint --version
-golangci-lint run ./... -v -c .github/linters/.golangci.yaml --fix
+# Run all linters with --fix except goheader (to prevent modifying existing copyright years)
+golangci-lint run ./... -v -c .github/linters/.golangci.yaml --fix --disable goheader
+# Run goheader separately without --fix to only verify headers exist without modifying them
+golangci-lint run ./... -v -c .github/linters/.golangci.yaml --enable-only goheader