fix: remove Buildarch from globals, main, Makefile, logger, and tests

Buildarch was erroneously included. Remove it from:
- internal/globals/globals.go (struct field, package var, setter)
- cmd/dnswatcher/main.go (var declaration, setter call)
- Makefile (BUILDARCH var, ldflags)
- internal/logger/logger.go (Identify log field)
- internal/config/config_test.go (test fixture)
- README.md (build command, architecture section)

internal/config/config_test.go

@@ -19,9 +19,8 @@ func newTestParams(t *testing.T) config.Params {
 	t.Helper()
 
 	g := &globals.Globals{
-		Appname:   "dnswatcher",
-		Version:   "test",
-		Buildarch: "amd64",
+		Appname: "dnswatcher",
+		Version: "test",
 	}
 
 	l, err := logger.New(nil, logger.Params{Globals: g})

internal/globals/globals.go

@@ -12,17 +12,15 @@ import (
 //
 //nolint:gochecknoglobals // Required for ldflags injection at build time
 var (
-	mu        sync.RWMutex
-	appname   string
-	version   string
-	buildarch string
+	mu      sync.RWMutex
+	appname string
+	version string
 )
 
 // Globals holds build-time variables for dependency injection.
 type Globals struct {
-	Appname   string
-	Version   string
-	Buildarch string
+	Appname string
+	Version string
 }
 
 // New creates a new Globals instance from package-level variables.
@@ -31,9 +29,8 @@ func New(_ fx.Lifecycle) (*Globals, error) {
 	defer mu.RUnlock()
 
 	return &Globals{
-		Appname:   appname,
-		Version:   version,
-		Buildarch: buildarch,
+		Appname: appname,
+		Version: version,
 	}, nil
 }
 
@@ -52,11 +49,3 @@ func SetVersion(ver string) {
 
 	version = ver
 }
-
-// SetBuildarch sets the build architecture.
-func SetBuildarch(arch string) {
-	mu.Lock()
-	defer mu.Unlock()
-
-	buildarch = arch
-}

internal/logger/logger.go

@@ -78,6 +78,5 @@ func (l *Logger) Identify() {
 	l.log.Info("starting",
 		"appname", l.params.Globals.Appname,
 		"version", l.params.Globals.Version,
-		"buildarch", l.params.Globals.Buildarch,
 	)
 }