refactor(repo): consolidate openflare-server to root and move subprojects to internal/apps

- Merge all files inside openflare-server to the repository root directory.
- Relocate agent, relay, and flared subprojects from internal/ to internal/apps/.
- Combine docker-compose files and update build context paths to root.
- Update GitHub workflows and Dockerfiles to refer to new directories and package names.
- Rewrite Go package imports across all files.
- Resolve database renew test race condition and clean up docs.

internal/apps/agent/logging/logger.go

@@ -0,0 +1,29 @@
+package logging
+
+import (
+	"log/slog"
+	"os"
+	"strings"
+)
+
+func Setup() {
+	opts := &slog.HandlerOptions{
+		AddSource: true,
+		Level:     parseLevel(os.Getenv("LOG_LEVEL")),
+	}
+	handler := slog.NewTextHandler(os.Stdout, opts)
+	slog.SetDefault(slog.New(handler))
+}
+
+func parseLevel(value string) slog.Level {
+	switch strings.ToLower(strings.TrimSpace(value)) {
+	case "debug":
+		return slog.LevelDebug
+	case "warn", "warning":
+		return slog.LevelWarn
+	case "error":
+		return slog.LevelError
+	default:
+		return slog.LevelInfo
+	}
+}