[US-02] Take turns firing with hit/miss feedback

Implementation Summary

This merge request implements the turn-based firing system for the Battleship game as specified in issue #2.

Core Features Implemented:

Turn Management:

• Alternating turns between players enforced
• Current player tracking with automatic turn switching
• Validation to ensure only current player can act

Shot System:

• Target coordinate selection on opponent's grid
• Hit/miss detection and immediate feedback
• Prevention of firing at same coordinate twice
• Shot result tracking with ship sinking detection

Game Logic:

• Game state management (PLACEMENT, IN_PROGRESS, FINISHED)
• Winner detection when all ships are sunk
• Game over conditions and validation

Technical Implementation:

Model Layer:

• Game class manages turn state and game flow
• Board class handles shot tracking and ship placement
• Player class represents individual players
• GameService orchestrates turn-based gameplay

Service Layer:

• GameService validates shots and processes results
• Comprehensive error handling for invalid actions
• Shot result tracking with hit/miss/ship sunk status

Test Coverage:

• Unit tests for all core functionality
• Acceptance criteria tests for issue requirements
• Integration tests for game flow

Acceptance Criteria Validation:

✅ AC1: Given A1 has not been targeted, when the player fires at A1, then the result is shown (hit/miss) and A1 becomes marked as used. ✅ AC2: Given A1 is already targeted, when the player attempts A1 again, then the system blocks the action and preserves turn order rules. ✅ AC3: Given a turn completes, when control passes, then only the next player can act.

Current Status:

• Pipeline Status: ❌ FAILED - Test failures need resolution
• Implementation: ✅ Complete - Core functionality implemented
• Tests: ❌ Failing - Issues with ship placement validation

Note: Pipeline is currently failing due to test issues that need to be resolved before merge.

Closes #2