Add TaskLevel Model for Complexity & Prerequisites

[arkid15r]

Describe the solution you'd like

We want to introduce a TaskLevel model to help categorize tasks by their complexity and context. This model will be used to:

• Link each Task to a level of difficulty
• Define prerequisites (needs) using a self-referential many-to-many field
• Map levels to specific GitHub labels

This will make it easier to assign appropriate tasks to mentees and create a structured progression system.

Goals:

• Introduce a flexible TaskLevel model
• Link each Task to a TaskLevel
• Use GitHub labels to reflect task levels externally

Possible structure:

class TaskLevel(models.Model):
    name = models.CharField()
    description = models.TextField()
    github_labels = models.JSONField(default=list)
    module = models.ForeignKey(Module...)
    needs = models.ManyToManyField("self"...)


class Task(models.Model):
    ...
    level = models.ForeignKey(TaskLevel...)

A mentor needs to have a UI to manage TaskLevels for a specific module. The labels field can be populated on existing repository labels