[FEAT]: Modify minigame rewards to give coins and gems instead food

[coxmars]

Issue

Adapt Minigame Rewards to Give Virtual Currencies Instead of Food

Description

We need to modify the minigame reward system to grant virtual currencies (coins and stones) as rewards instead of food items. This change will better align the reward system with the game's economy and provide more flexible rewards for players.

Explanation

Currently minigames provide food as rewards, but we want to transition to a virtual currency-based reward system. This will give players more control over how they spend their earned rewards and create a more balanced game economy.

Technical Spike Goals:

• Identify all minigame reward implementations that currently give food
• Replace food rewards with virtual currency rewards (coins)
• Implement reward calculation logic for different minigame performance levels
• Add currency reward distribution methods to player accounts
• Update minigame completion flow to handle currency rewards
• Create comprehensive tests for new virtual currency reward system