Introduce Quest Difficulty Tiers

[Mkalbani]

Description

All quests currently have the same reward structure regardless of complexity or challenge level.

Expected Behavior

Quests should have difficulty tiers that influence reward multipliers.

Proposed Changes

enum Difficulty { Easy, Medium, Hard, Legendary }

• Add Difficulty difficulty to the quest struct
• Apply reward multipliers: Easy 1x, Medium 1.5x, Hard 2x, Legendary 3x

Acceptance Criteria

• Difficulty is set at quest creation
• Reward payout respects the difficulty multiplier
• Tests cover all four difficulty levels

[Lynndabel]

@Lynndabel has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hello maintainer, i have gone through the task description and will like to work on this please. ETA: 6hours

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Lynndabel to this issue.