refactor: reorganize codebase into modular packages

feat(global): add global package for shared variables and types
refactor(handlers): move handlers to dedicated package and update imports
refactor(session): extract session management to separate package
refactor(config): move config handling to dedicated package
refactor(router): update route handlers to use new package structure
refactor(main): simplify main.go by moving logic to packages

global/global.go

@@ -0,0 +1,40 @@
+package global
+
+import (
+	"database/sql"
+)
+
+type SoftwareInfo struct {
+	Name        string
+	Version     string
+	Developer   string
+	BuildVer    int16
+	Description string
+	BuildType   string
+}
+
+type StatusFlags struct {
+	Debug             bool
+	Online            bool
+	WatchdogConnected bool
+}
+
+var (
+	ConfigDB *sql.DB
+	FrpcDB   *sql.DB
+	LogsDB   *sql.DB
+)
+
+var Software = SoftwareInfo{
+	Name:      "Super-frpc",
+	Version:   "0.0.1",
+	Developer: "Madobi Nanami",
+	BuildVer:  1,
+	BuildType: "debug",
+}
+
+var Is = StatusFlags{
+	Debug:             false,
+	Online:            false,
+	WatchdogConnected: false,
+}