refactor(logger): choose the console backend with build tags

The runtime.GOOS switch compiled the syslog branch into Windows builds,
where go-logging's syslog stub always returns an error. staticcheck
therefore reported SA4023 at logger.go:95 on every Windows lint run,
keeping `make lint-go` red on a clean main there while Linux CI never
saw it. console_windows.go and console_other.go now pick the backend at
build time, with each platform's behaviour unchanged.

No test can observe build-tag selection: `golangci-lint run` on Windows
goes from 1 issue to 0, and `GOOS=linux golangci-lint run
./internal/logger/...` stays clean.

internal/logger/console_windows.go

@@ -0,0 +1,14 @@
+//go:build windows
+
+package logger
+
+import (
+	"os"
+
+	"github.com/op/go-logging"
+)
+
+// newConsoleBackend logs to stderr: go-logging has no syslog on Windows.
+func newConsoleBackend() (backend logging.Backend, includeTime bool) {
+	return logging.NewLogBackend(os.Stderr, "", 0), true
+}