Add aim helper targeting tools

[Francis20066]

Introduce a floating aim helper window on the game screen so local human players in normal-function mode can collect target coordinates by clicking the map or entering x/y values manually.

Generate a piecewise linear function from the current soldier through the selected target points, respecting the current player's firing direction and validating the generated expression before sending it as a function preview.

Add undo, reset, point-count, status, and Ctrl+Z interactions so players can iterate on target selections without leaving the game screen.

Render numbered orange target markers and connecting guide lines on the graph plane, including reversed-terrain display handling for team-two viewpoints.

Display each soldier's game-space coordinates below their name so target selection can be checked against visible board positions.

[Francis20066]

Which Use

$$ f(x)=k_0x+b_0+\sum_i (k_i-k_{i-1})\frac{x-a_i+\lvert x-a_i\rvert}{2}$$

[Cmd-GZ]

Bro wanna make a built-in cheating system in the game 💀️