refactor: harden sqlite runtime and packaged startup flow

- refine config loading with --config and current-directory .env

- improve sqlite busy handling and runtime DB tuning

- restore telegram payment notification and wallet input flow

- add behavior-based config and callback recovery tests

src/model/dao/sqlite_config.go

@@ -0,0 +1,35 @@
+package dao
+
+import (
+	"database/sql"
+
+	"gorm.io/gorm"
+)
+
+func configureSQLite(db *gorm.DB, maxOpenConns int) (*sql.DB, error) {
+	sqlDB, err := db.DB()
+	if err != nil {
+		return nil, err
+	}
+
+	if maxOpenConns <= 0 {
+		maxOpenConns = 1
+	}
+	sqlDB.SetMaxOpenConns(maxOpenConns)
+	sqlDB.SetMaxIdleConns(1)
+
+	if err := db.Exec("PRAGMA journal_mode=WAL;").Error; err != nil {
+		return nil, err
+	}
+	if err := db.Exec("PRAGMA synchronous=NORMAL;").Error; err != nil {
+		return nil, err
+	}
+	if err := db.Exec("PRAGMA busy_timeout=5000;").Error; err != nil {
+		return nil, err
+	}
+	if err := sqlDB.Ping(); err != nil {
+		return nil, err
+	}
+
+	return sqlDB, nil
+}