fix(portfolio-contract): Propagate graph arc minimum flow into LP solver input

Author: gibson042

packages/portfolio-contract/tools/network/buildGraph.ts

@@ -21,6 +21,7 @@ export interface FlowEdge {
   src: AssetPlaceRef;
   dest: AssetPlaceRef;
   capacity?: number; // numeric for LP; derived from bigint
+  min?: number; // numeric for LP; derived from bigint
   variableFee: number; // cost coefficient per unit flow in basis points
   fixedFee?: number; // optional fixed cost (cheapest mode)
   timeFixed?: number; // optional time cost (fastest mode)
@@ -260,6 +261,7 @@ export const makeGraphFromDefinition = (
   for (const link of spec.links) {
     addOrReplaceEdge(link.src, link.dest, {
       capacity: link.capacity === undefined ? undefined : Number(link.capacity),
+      min: link.min === undefined ? undefined : Number(link.min),
       variableFee: link.variableFeeBps ?? 0,
       fixedFee: link.flatFee === undefined ? undefined : Number(link.flatFee),
       timeFixed: link.timeSec,

packages/portfolio-contract/tools/network/network-spec.ts

@@ -90,8 +90,8 @@ export interface LinkSpec {
   feeMode?: FeeMode; // how fees apply to transation using this link. See plan-solve.ts
 
   // Policy / guardrails (optional)
-  priority?: number; // tie-break hint
-  enabled?: boolean; // admin toggle
+  // priority?: number; // tie-break hint
+  // enabled?: boolean; // admin toggle
 }
 
 // Overall network definition

packages/portfolio-contract/tools/plan-solve.ts

@@ -145,11 +145,12 @@ export const buildLPModel = (
   let minPrimaryWeight = Infinity;
   for (const edge of graph.edges) {
     const { id, src, dest } = edge;
-    const { capacity, variableFee, fixedFee = 0, timeFixed = 0 } = edge;
+    const { capacity, min, variableFee, fixedFee = 0, timeFixed = 0 } = edge;
 
-    const throughputConstraint: { min: number; max?: number } = { min: 0 };
-    if (capacity) throughputConstraint.max = capacity;
-    throughputConstraints[`through_${id}`] = throughputConstraint;
+    throughputConstraints[`through_${id}`] = {
+      min: min || 0,
+      max: capacity,
+    };
 
     // The numbers in graph.supplies should use the same units as fixedFee, but
     // variableFee is in basis points relative to some scaling of those other
@@ -297,6 +298,7 @@ SUBJECT TO
       const prefix = attrParts.join('_');
       const lines = [`\\# ${attr} ${prettyJsonable(constraint)}`];
       for (const [opName, value] of Object.entries(constraint)) {
+        if (!Number.isFinite(value)) continue;
         const label = `${prefix}_${opName.slice(0, 3)}`;
         const op = cplexLpOpForName[opName];
         lines.push(`${label}: ${makeSumExpr(attr)} ${op} ${value}`);