reasoning: use structured semantic fidelity contract

tests/graph/schema.test.js

@@ -4,6 +4,8 @@ import {
   SituationStatus,
   ConfidenceLevel,
   SituationRelationship,
+  answerResolutionGuidance,
+  answerSupportCategory,
   situationNodeSchema,
   situationEdgeSchema,
   situationGraphSchema,
@@ -212,13 +214,39 @@ describe("graphUpdateSchema", () => {
         userSupportedMeaning: "Risk matters more to me.",
         possibleInference:
           "This may imply caution, but does not establish a hard constraint.",
-        supportCategory: "relative priority only",
-        resolutionGuidance: "leave unresolved",
+        supportCategory: answerSupportCategory.relative_priority_only,
+        resolutionGuidance: answerResolutionGuidance.must_remain_unresolved,
       },
     });
     expect(result.success).toBe(true);
   });
 
+  it("rejects invalid supportCategory values", () => {
+    const result = graphUpdateSchema.safeParse({
+      answerMeaning: {
+        userSupportedMeaning: "Risk matters more to me.",
+        possibleInference: null,
+        supportCategory: "relative priority only",
+        resolutionGuidance: answerResolutionGuidance.must_remain_unresolved,
+      },
+    });
+
+    expect(result.success).toBe(false);
+  });
+
+  it("rejects invalid resolutionGuidance values", () => {
+    const result = graphUpdateSchema.safeParse({
+      answerMeaning: {
+        userSupportedMeaning: "Risk matters more to me.",
+        possibleInference: null,
+        supportCategory: answerSupportCategory.relative_priority_only,
+        resolutionGuidance: "leave unresolved",
+      },
+    });
+
+    expect(result.success).toBe(false);
+  });
+
   it("rejects update with invalid node kind in addedNodes", () => {
     const invalid = graphUpdateSchema.safeParse({
       addedNodes: [