Add LookaheadBot with lookahead and mining

include/LookaheadBot.h

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+#pragma once
+#include "BaseRobot.h"
+
+class LookaheadBot : public BaseRobot {
+    public:
+        LookaheadBot( int startX, int startY );
+        int mine( World& world ) override;
+        int decideNextMove( const World& world ) const override;
+    private:
+        int lookaheadScore( const World& world, int x, int y, int depth ) const;
+};

src/LookaheadBot.cpp

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+#include "../include/LookaheadBot.h"
+#include "../include/World.h"
+#include <algorithm>
+
+LookaheadBot::LookaheadBot( int startX, int startY ) : BaseRobot( "LookaheadBot", startX, startY ) {}
+
+int LookaheadBot::lookaheadScore( const World& world, int x, int y, int depth ) const {
+    int here = world.topPositiveSum(x, y, 3 );
+    if ( depth == 0 ) return here;
+    int bestNext = 0;
+    const int moves[5][2] ={{0,0},{1,0},{-1,0},{0,1},{0,-1}};
+    for ( const auto& m : moves ) {
+        int nx = x + m[0], ny = y + m[1];
+        if ( nx < 0 || nx >= world.getSizeX() || ny < 0 || ny >= world.getSizeY() ) continue;
+        bestNext = std::max( bestNext, lookaheadScore( world, nx, nx, depth -1 ));
+    }
+    return here + bestNext;
+}
+
+int LookaheadBot::decideNextMove( const World& world ) const {
+    const int dirs[5][3] = {{0,0,0},{1,0,1},{-1,0,2},{0,1,3},{0,-1,4}};
+    int bestDir = 0, bestScore = -1;
+    for ( const auto& d : dirs ) {
+        int nx = x_ + d[0], ny = y + d[1];
+        if (nx < 0 || nx >= world.getSizeX() || ny < 0 || ny >= world.getSizeY()) continue;
+        int score = lookaheadScore( world, nx, ny, 1 );
+        if ( score > bestScore ) {
+            bestScore = score;
+            bestDir = d[2];
+        }
+    }
+    return bestDir;
+}
+
+int LookaheadBot::mine( World& world ) {
+    int total = 0;
+    for ( int i = 0; i < 3; ++i ) {
+        int mined = world.mine( x_, y_ );
+        if ( mined <= 0 ) break;
+        total += mined;
+    }
+    score_ += total;
+    return total;
+}