Use golangci-lint fmt to format code (#163)

Use `golangci-lint fmt` to format code, upgrading `.golangci.yml` to v2 and mirroring the linter configuration used by https://github.com/go-gitea/gitea. `gci` now handles import ordering into standard, project-local, blank, and default groups.

Mirrors https://github.com/go-gitea/gitea/pull/37194.

Changes:
- Upgrade `.golangci.yml` to v2 format with the same linter set as gitea (minus `prealloc`, `unparam`, `testifylint`, `nilnil` which produced too many pre-existing issues)
- Add path-based exclusions (`bodyclose`, `gosec` in tests; `gosec:G115`/`G117` globally)
- Run lint via `make lint-go` in CI instead of `golangci/golangci-lint-action`, matching the pattern used by other Gitea repos
- Apply safe auto-fixes (`modernize`, `perfsprint`, `usetesting`, etc.)
- Add explanations to existing `//nolint` directives
- Remove dead code (unused `newRemoteReusableWorkflow` and `networkName`), duplicate imports, and shadowed `max` builtins
- Replace deprecated `docker/distribution/reference` with `distribution/reference`
- Fix `Deprecated:` comment casing and simplify nil/len checks

---
This PR was written with the help of Claude Opus 4.7

Reviewed-on: https://gitea.com/gitea/act/pulls/163
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-committed-by: silverwind <me@silverwind.io>

pkg/common/executor.go

@@ -19,7 +19,7 @@ func (w Warning) Error() string {
 }
 
 // Warningf create a warning
-func Warningf(format string, args ...interface{}) Warning {
+func Warningf(format string, args ...any) Warning {
 	w := Warning{
 		Message: fmt.Sprintf(format, args...),
 	}
@@ -33,7 +33,7 @@ type Executor func(ctx context.Context) error
 type Conditional func(ctx context.Context) bool
 
 // NewInfoExecutor is an executor that logs messages
-func NewInfoExecutor(format string, args ...interface{}) Executor {
+func NewInfoExecutor(format string, args ...any) Executor {
 	return func(ctx context.Context) error {
 		logger := Logger(ctx)
 		logger.Infof(format, args...)
@@ -42,7 +42,7 @@ func NewInfoExecutor(format string, args ...interface{}) Executor {
 }
 
 // NewDebugExecutor is an executor that logs messages
-func NewDebugExecutor(format string, args ...interface{}) Executor {
+func NewDebugExecutor(format string, args ...any) Executor {
 	return func(ctx context.Context) error {
 		logger := Logger(ctx)
 		logger.Debugf(format, args...)
@@ -69,7 +69,7 @@ func NewPipelineExecutor(executors ...Executor) Executor {
 }
 
 // NewConditionalExecutor creates a new executor based on conditions
-func NewConditionalExecutor(conditional Conditional, trueExecutor Executor, falseExecutor Executor) Executor {
+func NewConditionalExecutor(conditional Conditional, trueExecutor, falseExecutor Executor) Executor {
 	return func(ctx context.Context) error {
 		if conditional(ctx) {
 			if trueExecutor != nil {
@@ -128,14 +128,14 @@ func NewParallelExecutor(parallel int, executors ...Executor) Executor {
 			}(i, work, errs)
 		}
 
-		for i := 0; i < len(executors); i++ {
+		for i := range executors {
 			work <- executors[i]
 		}
 		close(work)
 
 		// Executor waits all executors to cleanup these resources.
 		var firstErr error
-		for i := 0; i < len(executors); i++ {
+		for range executors {
 			err := <-errs
 			if firstErr == nil {
 				firstErr = err