feat(FN-4400): complete Step 2 — add heartbeat prompt template settings

Fusion-Task-Id: FN-4400
Fusion-Task-Lineage: 0d4f9c48-5b8b-49eb-9cf3-d1d585ffe7fc

packages/core/src/__tests__/settings-parity.test.ts

@@ -95,6 +95,12 @@ describe("settings key parity", () => {
     expect(isGlobalSettingsKey("heartbeatScopeDiscipline")).toBe(false);
   });
 
+  it("keeps heartbeatPromptTemplate project-scoped with default default", () => {
+    expect(DEFAULT_PROJECT_SETTINGS.heartbeatPromptTemplate).toBe("default");
+    expect(isProjectSettingsKey("heartbeatPromptTemplate")).toBe(true);
+    expect(isGlobalSettingsKey("heartbeatPromptTemplate")).toBe(false);
+  });
+
   it("documents autoClaimCandidatesInPrompt expected integer range", () => {
     const inRange = [0, 1, 5, 10];
     const outOfRange = [-1, 11, 100];

packages/core/src/__tests__/settings-validation.test.ts

@@ -3,6 +3,7 @@ import {
   validateDirectMergeCommitStrategy,
   validateGithubAuthMode,
   validateGithubRepoSlug,
+  validateHeartbeatPromptTemplate,
   validateHeartbeatScopeDisciplineMode,
   validateUnavailableNodePolicy,
 } from "../settings-validation.js";
@@ -62,6 +63,19 @@ describe("settings-validation", () => {
     });
   });
 
+  describe("validateHeartbeatPromptTemplate", () => {
+    it("accepts supported templates", () => {
+      expect(validateHeartbeatPromptTemplate("default")).toBe("default");
+      expect(validateHeartbeatPromptTemplate("compact")).toBe("compact");
+    });
+
+    it("returns undefined for invalid values", () => {
+      expect(validateHeartbeatPromptTemplate("tiny")).toBeUndefined();
+      expect(validateHeartbeatPromptTemplate(123)).toBeUndefined();
+      expect(validateHeartbeatPromptTemplate(undefined)).toBeUndefined();
+    });
+  });
+
   describe("validateGithubRepoSlug", () => {
     it("accepts valid owner/repo slugs", () => {
       expect(validateGithubRepoSlug("owner/repo")).toBe("owner/repo");