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/flared/config/config.go

@@ -0,0 +1,158 @@
+package config
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+type MillisecondDuration time.Duration
+
+func (d *MillisecondDuration) UnmarshalJSON(b []byte) error {
+	var v interface{}
+	if err := json.Unmarshal(b, &v); err != nil {
+		return err
+	}
+	switch value := v.(type) {
+	case float64:
+		*d = MillisecondDuration(time.Duration(value) * time.Millisecond)
+		return nil
+	case string:
+		duration, err := time.ParseDuration(value)
+		if err != nil {
+			return err
+		}
+		*d = MillisecondDuration(duration)
+		return nil
+	default:
+		return errors.New("invalid duration format")
+	}
+}
+
+func (d MillisecondDuration) Duration() time.Duration {
+	return time.Duration(d)
+}
+
+func (d MillisecondDuration) String() string {
+	return time.Duration(d).String()
+}
+
+type Config struct {
+	ServerURL         string              `json:"server_url"`
+	TunnelToken       string              `json:"tunnel_token"`
+	FrpcPath          string              `json:"frpc_path"`
+	DataDir           string              `json:"data_dir"`
+	StatePath         string              `json:"state_path"`
+	HeartbeatInterval MillisecondDuration `json:"heartbeat_interval"`
+	SyncInterval      MillisecondDuration `json:"sync_interval"`
+	RequestTimeout    MillisecondDuration `json:"request_timeout"`
+	configPath        string
+}
+
+func Load(path string) (*Config, error) {
+	data, err := os.ReadFile(path)
+	if err != nil && !os.IsNotExist(err) {
+		return nil, err
+	}
+	cfg := &Config{}
+	if err == nil {
+		if err = json.Unmarshal(data, cfg); err != nil {
+			return nil, err
+		}
+	}
+	if err != nil && !hasEnvConfig() {
+		return nil, err
+	}
+	cfg.configPath = path
+	applyEnvOverrides(cfg)
+	applyDefaults(cfg, filepath.Dir(path))
+	if err = validate(cfg); err != nil {
+		return nil, err
+	}
+	return cfg, nil
+}
+
+func hasEnvConfig() bool {
+	for _, key := range []string{
+		"OPENFLARE_SERVER_URL",
+		"OPENFLARE_TUNNEL_TOKEN",
+		"OPENFLARE_DATA_DIR",
+		"OPENFLARE_FRPC_PATH",
+	} {
+		if strings.TrimSpace(os.Getenv(key)) != "" {
+			return true
+		}
+	}
+	return false
+}
+
+func applyEnvOverrides(cfg *Config) {
+	if cfg == nil {
+		return
+	}
+	overrideString := func(key string, target *string) {
+		if value := strings.TrimSpace(os.Getenv(key)); value != "" {
+			*target = value
+		}
+	}
+	overrideString("OPENFLARE_SERVER_URL", &cfg.ServerURL)
+	overrideString("OPENFLARE_TUNNEL_TOKEN", &cfg.TunnelToken)
+	overrideString("OPENFLARE_DATA_DIR", &cfg.DataDir)
+	overrideString("OPENFLARE_FRPC_PATH", &cfg.FrpcPath)
+}
+
+func applyDefaults(cfg *Config, baseDir string) {
+	baseDir = filepath.Clean(baseDir)
+	if cfg.FrpcPath == "" {
+		cfg.FrpcPath = "frpc" // rely on PATH
+	}
+	if cfg.DataDir == "" {
+		cfg.DataDir = filepath.Join(baseDir, "data")
+	}
+	if cfg.StatePath == "" {
+		cfg.StatePath = filepath.Join(cfg.DataDir, "flared-state.json")
+	}
+	if cfg.HeartbeatInterval <= 0 {
+		cfg.HeartbeatInterval = MillisecondDuration(10 * time.Second)
+	}
+	if cfg.SyncInterval <= 0 {
+		cfg.SyncInterval = MillisecondDuration(30 * time.Second)
+	}
+	if cfg.RequestTimeout <= 0 {
+		cfg.RequestTimeout = MillisecondDuration(10 * time.Second)
+	}
+}
+
+func validate(cfg *Config) error {
+	if cfg.ServerURL == "" {
+		return errors.New("server_url 不能为空")
+	}
+	if strings.TrimSpace(cfg.TunnelToken) == "" {
+		return errors.New("tunnel_token 不能为空")
+	}
+	return nil
+}
+
+func (cfg *Config) InitialAuthToken() string {
+	if cfg == nil {
+		return ""
+	}
+	return strings.TrimSpace(cfg.TunnelToken)
+}
+
+func (cfg *Config) Save() error {
+	if cfg == nil {
+		return errors.New("config 不能为空")
+	}
+	if cfg.configPath == "" {
+		return errors.New("config path 未初始化")
+	}
+	data, err := json.MarshalIndent(cfg, "", "  ")
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(cfg.configPath, data, 0o644)
+}

internal/apps/flared/config/version.go

@@ -0,0 +1,3 @@
+package config
+
+var Version = "dev"