Default tags: keep warning and error, move ok to the Log levels preset

Existing tags.json files are unchanged; only new installs and "Restore
default tags" get the shorter list.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tags.go

@@ -30,7 +30,6 @@ func defaultTags() []Tag {
 	return []Tag{
 		{ID: "warning", Code: "01", Pattern: "warning", Color: "#fdba74", WholeWord: true, Enabled: true},
 		{ID: "error", Code: "02", Pattern: "error", Color: "#fca5a5", WholeWord: true, Enabled: true},
-		{ID: "ok", Code: "03", Pattern: "ok", Color: "#86efac", WholeWord: true, Enabled: true},
 	}
 }