Half favour for bank overflow

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

game.py

@@ -18,6 +18,7 @@ BASE_SLOTS = 12
 BASE_STACK = 1000
 CLASS_SPEED = 0.8
 LUCKY_CHANCE = 0.1
+OVERFLOW_FAVOUR = 0.5   # favour for items a full bank spills to the city, vs. giving on purpose
 RECON_PER_INTEL = 8
 MAX_LOG = 200
 REGEN_PER_HOUR = 0.25   # share of max HP recovered per game hour
@@ -452,7 +453,7 @@ def bank_add(world: dict, player: dict, item: str, qty: int, now: float, overflo
         stockpile = world["city"]["stockpile"]
         stockpile[item] = stockpile.get(item, 0) + spill
         gain = spill * ITEMS[item]["value"]
-        player["favour"] += gain
+        player["favour"] += gain * OVERFLOW_FAVOUR
         player["donated"] += gain
         overflow[item] = overflow.get(item, 0) + spill
     return keep