Add equipment effects, boss phase 2, locked chests, and combat enhancements

[phaax]

Summary

This PR introduces a comprehensive set of combat and equipment system enhancements, including equipment stat bonuses, boss phase transitions, locked chest mechanics, and various combat balance improvements.

Key Changes

Equipment System

• Added applyItemEffect() and removeItemEffect() functions to handle stat modifications when equipping/unequipping items
• Implemented support for multiple effect types: HP/MP bonuses, stat increases, defense bonuses, fire damage, dodge chance, and curses
• Added getEffectDescription() to display human-readable effect descriptions in the inventory UI
• Updated inventory screen to show equipment effects and handle cursed item warnings
• Added helmet defense calculation to getPlayerDefense()

Combat Enhancements

• Implemented strength boost potion mechanic: str_boost effect grants +2 STR for 5 turns with turn counter management
• Added fire damage bonus from accessories (Ring of Fire) to player attacks
• Added luck bonus from accessories to dodge chance calculations
• Improved dodge chance comment to reflect all contributing factors (race traits, skills, accessories)

Boss Phase 2 System

• Bosses now enter "RAGE" phase when HP drops below 50%
• Phase 2 triggers increased damage for boss abilities:
  • Fire breath: 3d8 → 4d12
  • Inferno: 5d10 → 7d15
  • Death bolt: 4d10 → 6d15
  • Drain life: 20 HP → 30 HP
• Boss melee attacks deal 30% more damage in phase 2

Locked Chest Mechanics

• 30% of generated chests are now locked
• Lockpicking skill provides 80% success rate; lockpick item alone provides 50%
• Lockpick items break on failed attempts (when used without skill)
• Appropriate system messages for success/failure states

UI Improvements

• Inventory screen now displays equipment effects with color coding (cyan for normal, magenta for cursed)
• Dynamic layout for item details to accommodate effect descriptions
• Added cursed item indicator on equipped items
• Improved item stat display formatting

Implementation Details

• Strength boost counter decrements at the start of each player turn with system message on expiration
• Equipment effects are properly applied/removed when swapping items in the same slot
• Boss phase state is tracked via monster.currentPhase property
• Accessory bonuses use underscore-prefixed player properties (_bonusDef, _fireDmgBonus, _luckBonus)

https://claude.ai/code/session_01EhQjxFs3KkqgUTyt8KsK6S