Gene Passion Restore Fix

Fixes a vanilla bug where removing a great skill gene permanently reduces passion by one level.
pawn's skill details, a "base passion" line appears

When a gene with "Add One Passion Level" is removed, vanilla always decrements the pawn's current passion by one level, regardless of what the passion was before the gene was added.

Example:
Pawn has ★★ passion naturally.
Install a gene that adds one passion level → passion stays ★★ (already at max).
Remove the gene → vanilla decrements ★★ to ★. Passion is permanently lost.

When a gene is added to a pawn at runtime (surgery, gene assembler), the game records the pawn's passion at that moment as the "base passion." On removal, this mod restores that saved value instead of decrementing.

Vanilla: remove gene → passion −1 (permanent loss)
This mod: remove gene → passion restored to what it was before the gene was added

If a pawn is born or spawned with the passion-boosting gene already present (e.g. enemy raiders, certain xenotypes), no base passion record exists for that gene. In this case the mod falls back to vanilla behavior (passion −1). There is no regression compared to vanilla.

When viewing a pawn's skill details, a "base passion" line appears under gene aptitude entries. This shows the passion the pawn would have if the gene were removed — useful when deciding whether to replace a xenogerm.
If no base passion record exists for the gene (pawn spawned with it), the value shown is an estimate derived by reversing the gene's effect.

Requires Biotech DLC.