Major game update: Multiple crops, seasons, economy, and watering systems

[Copilot]

Comprehensive feature expansion based on the roadmap in README. Adds core farming mechanics: crop variety, seasonal planting, economy loop, and growth acceleration via watering.

New Systems

• 5 Crop Types: Wheat (spring), Tomato/Corn (summer), Pumpkin/Carrot (autumn) with distinct growth times, prices, colors
• Season Cycle: 4-season rotation affecting which crops can be planted; background color reflects current season
• Economy: Gold currency, buy seeds from shop (B key), sell products from inventory (Q key)
• Watering: Watering can tool (R key) applies 1.5x growth speed boost
• Inventory Stacking: Items now stack with count display

Player Improvements

• Character direction changes based on movement
• HUD showing gold, season/day, selected seed
• TAB cycles through seed selection
• Notification system for action feedback

Code Quality

• ItemID constants replace magic numbers
• Time constants extracted (SEASON_DURATION = 120 * 1000)
• Fixed RGBA handling for transparent surfaces
• Module-level imports to avoid circular dependencies

# Before: magic numbers
hoe = Item(1, "Hoe", ItemType.TOOL, ...)
has_hoe = player.has_item(1)

# After: named constants
hoe = Item(ItemID.HOE, "Hoe", ItemType.TOOL, ...)
has_hoe = player.has_item(ItemID.HOE)

Removed deprecated import pygame.py backup file.

Original prompt

全全按照你的想法来更新这个游戏

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