Pure attack functions (Attack Layer)

[Hardcode3]

🎯 Goal

Extract a pure attack layer, fully independent from legality, colors, kings, or move objects.

🧠 Key Idea

An *_attacks() function:

• returns a Bitboard
• depends only on (Square from, Bitboard occupied)
• never creates a Move

🛠️ Tasks

Implement sliders (occupancy dependent attacks):

• bishop_attacks(from, occupied)
• rook_attacks(from, occupied)
• queen_attacks = bishop | rook

Implement non sliders (occupancy independent attacks):

• knight_attacks[from]

• king_attacks[from]

• pawn_attacks(color, from)

• Rename ambiguous functions (generate_* -> *_attacks)

• Ensure no board or color logic leaks into this layer

✅ Acceptance Criteria

• Attacks match the old pseudo-legal generators
• No legality filtering
• No move creation