Fix mirrored ball kick velocity on inverted fullsystem tab

[annieisawesome2]

Description

Fixes mirrored ball kick behaviour on the yellow fullsystem.

When placing the ball with Shift+click and Shift+drag, the Blue and Yellow tabs can use different coordinate frames depending on friendly_colour_yellow and referee.blue_team_on_positive_half. On the inverted tab, the move preview line pointed toward the mouse (opposite of the intended slingshot direction).

Changes made:
Converted simulator-space velocity to display-space for rendering.
Use it when drawing the kick preview line so drag-back to shoot-forward matches blue fullsystem.

On release, negate velocity into a local ball_velocity before sending to the simulator (instead of mutating self.ball_velocity_vector), so preview and simulator send stay consistent

Testing Done

Try the shift click on both blue and yellow fullsystems.

Screen.Recording.2026-07-04.at.7.37.26.AM.mov

Resolved Issues

#3761

Length Justification and Key Files to Review

Review Checklist

It is the reviewers responsibility to also make sure every item here has been covered

• Function & Class comments: All function definitions (usually in the .h file) should have a javadoc style comment at the start of them. For examples, see the functions defined in thunderbots/software/geom. Similarly, all classes should have an associated Javadoc comment explaining the purpose of the class.
• Remove all commented out code
• Remove extra print statements: for example, those just used for testing
• Resolve all TODO's: All TODO (or similar) statements should either be completed or associated with a github issue

[nycrat]

@annieisawesome2 could you update this PR with the fixes we talked about in-person when you have time?

[annieisawesome2]

@annieisawesome2 could you update this PR with the fixes we talked about in-person when you have time?

Updated! Sorry for the delay.

[nycrat]

Good work! Just make sure to pull from master for a bugfix that is causing ci to fail