Improve plot update performance by reusing Matplotlib artists

[PumpGame]

Motivation

• The interactive plot was triggering full redraws on many operations which made the UI sluggish and unresponsive.
• The goal is to speed up pan/zoom/drag/selection interactions by avoiding unnecessary recreation of plot objects.

Description

• Added cached artist attributes basemap_artist, track_line, and scatter and reset them on full redraws to enable reuse.
• Updated _update_plot to update existing artists (set data/offsets/extent) instead of calling plot/scatter/imshow every time, and to remove the basemap artist when map is disabled.
• Recreate the info box only when necessary by checking full or whether self.info_text is present in self.ax.texts to avoid extra text objects.
• Kept existing selection, undo/redo and KD-tree logic unchanged while ensuring artists stay in sync with data updates.

Testing

• No automated tests were executed.

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Codex Task