MGS Origins Expanded 3.9.1 — Additive Firearm Affinities

Design rule: every affinity is appended to the Origin power list.
Existing Firearms/Firearms Specialist powers are preserved unchanged.
The new affinity adds only an extra projectile-damage modifier while the
matching firearm is held in the main hand.

Supported weapon mappings:
- big_boss: M1911A1 Firearm Familiarity (+20%) -> tacz:m1911, pointblank:m1911a1
- solid_snake: SOCOM & M4 Firearm Familiarity (+20%) -> tacz:hk_mk23, tacz:m4a1, pointblank:m4a1, pointblank:usp45
- old_snake: M4 & SOCOM Firearm Familiarity (+20%) -> tacz:m4a1, tacz:hk_mk23, pointblank:m4a1, pointblank:m4sopmodii
- venom_snake: Service Rifle Familiarity (+20%) -> tacz:m4a1, pointblank:m4a1, pointblank:m4a1mod1, pointblank:m4sopmodii
- revolver_ocelot: Revolver Familiarity (+20%) -> tacz:rhino357, tacz:taurus500, tacz:springfield1873, pointblank:rhino
- meryl: Desert Eagle Familiarity (+20%) -> tacz:deagle, pointblank:deserteagle
- vulcan_raven: Heavy Machine Gun Familiarity (+20%) -> tacz:minigun, pointblank:m134minigun
- quiet: Precision Rifle Familiarity (+20%) -> tacz:m700, tacz:m107, pointblank:l96a1, pointblank:wa2000
- olga_gurlukovich: AK Platform Familiarity (+20%) -> tacz:ak47, pointblank:ak47, pointblank:ak74
- eva: M1911A1 Familiarity (+20%) -> tacz:m1911, pointblank:m1911a1
