give every recipe one shape: a list of output groups

Implements REQ-MAT-OUTPUT-GROUP. A recipe had two shapes -- outputs produced
together, or outputs of which exactly one happened -- and every rule over them
was written twice, selected by `building == ReprocessingPlant`: sizing a
buffer, deciding whether a cycle fits, resolving what a cycle makes, costing an
item. RecipeDef now holds output groups, each a weight and a list of items, and
a cycle yields exactly one group. One group is the ordinary recipe, so the old
two cases are the same shape with one and with several, and all four rules
collapse to one expression apiece with no building-type test left.

rollReprocessingOutput becomes rollOutputGroup, where a single group returns
without drawing or testing eligibility. That early-out is load-bearing twice
over. Drawing there would consume entropy for every ordinary recipe and shift
every later random outcome; and eligibility must not apply either, since
implicit unlocking is demand-derived, so an ordinary recipe's output can be
producible while nothing yet calls for it -- testing it would stop the building
producing rather than gate a drop. Past the early-out a group is eligible only
when all of its items are unlocked, being produced whole.

Threat follows the recipe's shape rather than the building, and the per-unit
value now divides by the group's amount as well as its odds. That moves no
number today: every item resolved through this path has amount 1, which is why
the threat expectations are untouched.

Config keeps `outputs = [...]` as the single-group form, so only the two
reprocessing recipes change shape. The recipe summary gains "/" between groups
and keeps "+" within one, which also fixes the plant reading as though a cycle
produced all of its items at once.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ne3mejABZoLWKLh8fgpM3x

src/lib/sim/BuildingBuffers.cpp

@@ -12,27 +12,27 @@
 namespace
 {
 
-// Folds the output capacities one recipe implies into `caps`: twice each produced
-// item's per-cycle amount (REQ-MAT-OUTPUT-BUFFER). A Reprocessing Plant rolls exactly
-// one of its outputs per cycle (REQ-BLD-REPROCESSING), so its per-cycle amount for an
-// item is that one outcome's amount rather than a sum over the entries.
+// Folds the output capacities one recipe implies into `caps`: twice each produced item's
+// per-cycle amount (REQ-MAT-OUTPUT-BUFFER). A cycle yields exactly one output group
+// (REQ-MAT-OUTPUT-GROUP), so an item's per-cycle amount is the largest total any single
+// group produces of it -- summed within a group, whose items come together, and taken at
+// its maximum across groups, of which only one ever happens.
 //
-// Where a cap is already present the larger wins, which is how an auto-recipe building
-// unions the recipes of its type -- the same rule its input caps follow.
-void addOutputCaps(std::map<ItemType, int>& caps, BuildingType type,
-                   const RecipeDef& recipe)
+// Where a cap is already present the larger wins, which is how a cap unions across the
+// recipes it could be sized over -- the same rule the input caps follow.
+void addOutputCaps(std::map<ItemType, int>& caps, const RecipeDef& recipe)
 {
     std::map<ItemType, int> perCycle;
-    for (const RecipeOutput& out : recipe.outputs)
+    for (const RecipeOutputGroup& group : recipe.outputGroups)
     {
-        const ItemType item{out.item};
-        if (type == BuildingType::ReprocessingPlant)
+        std::map<ItemType, int> inGroup;
+        for (const RecipeOutput& out : group.items)
         {
-            perCycle[item] = std::max(perCycle[item], out.amount);
+            inGroup[ItemType{out.item}] += out.amount;
         }
-        else
+        for (const std::pair<const ItemType, int>& entry : inGroup)
         {
-            perCycle[item] += out.amount;
+            perCycle[entry.first] = std::max(perCycle[entry.first], entry.second);
         }
     }
 
@@ -57,7 +57,7 @@ void initBuffers(Building& b, const RecipeDef& recipe)
 
     b.outputBuffer.items.clear();
     b.outputBuffer.caps.clear();
-    addOutputCaps(b.outputBuffer.caps, b.type, recipe);
+    addOutputCaps(b.outputBuffer.caps, recipe);
 }
 
 void initShipyardBuffers(const GameConfig& config, Building& b)