feat(sync): add academic data reset tool, configurable sheets URL and fix sync timeout

backend/app/models/__init__.py

@@ -10,6 +10,7 @@ from .role import Role, Permission, SYSTEM_MODULES
 from .milestone import MilestoneType, AcademicMilestone, BASE_MILESTONE_TYPES
 from .audit_log import AuditLog
 from .enrollment import StudentEnrollment
+from .setting import SystemSetting
 
 __all__ = [
     'User',
@@ -31,5 +32,6 @@ __all__ = [
     'AcademicMilestone',
     'BASE_MILESTONE_TYPES',
     'AuditLog',
-    'StudentEnrollment'
+    'StudentEnrollment',
+    'SystemSetting'
 ]

backend/app/models/setting.py

@@ -0,0 +1,50 @@
+from app import db
+from datetime import datetime
+
+class SystemSetting(db.Model):
+    """
+    Parámetros de configuración del sistema persistentes en base de datos.
+    Permite almacenar enlaces de integración (e.g. Google Sheets), flags globales y metadatos.
+    """
+    __tablename__ = 'system_settings'
+
+    id = db.Column(db.Integer, primary_key=True)
+    key = db.Column(db.String(100), unique=True, nullable=False, index=True)
+    value = db.Column(db.Text, nullable=True)
+    description = db.Column(db.String(255), nullable=True)
+    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+    @classmethod
+    def get_value(cls, key, default=None):
+        try:
+            record = cls.query.filter_by(key=key).first()
+            if record and record.value is not None and record.value.strip() != '':
+                return record.value
+        except Exception:
+            pass
+        return default
+
+    @classmethod
+    def set_value(cls, key, value, description=None):
+        record = cls.query.filter_by(key=key).first()
+        if not record:
+            record = cls(key=key, value=value, description=description)
+            db.session.add(record)
+        else:
+            record.value = value
+            if description:
+                record.description = description
+            record.updated_at = datetime.utcnow()
+        db.session.commit()
+        return record
+
+    def to_dict(self):
+        return {
+            'key': self.key,
+            'value': self.value,
+            'description': self.description,
+            'updated_at': self.updated_at.isoformat() if self.updated_at else None
+        }
+
+    def __repr__(self):
+        return f'<SystemSetting {self.key}={self.value}>'