feat(FN-4063): enforce planning and triage memory write contracts

Enforces memory write contracts for triage and planning agents, adding tests in both `project-memory.test.ts` and `triage.test.ts` to guard the contract boundaries established in `project-memory.ts`.

Fusion-Task-Id: FN-4063

Fusion-Task-Lineage: 5f86295b-d583-4757-9aa5-30a64b2cc2d6

packages/core/src/__tests__/project-memory.test.ts

@@ -536,6 +536,9 @@ describe("project-memory", () => {
       const instructions = buildTriageMemoryInstructions(testDir, settings);
       expect(instructions).toContain(".fusion/memory/MEMORY.md");
       expect(instructions).toContain("## Project Memory");
+      expect(instructions).toContain("fn_memory_append");
+      expect(instructions).toContain("Do **not** write");
+      expect(instructions).toContain("or any other memory files directly");
     });
 
     it("includes read-only wording for readonly backend without write directives", () => {
@@ -558,6 +561,8 @@ describe("project-memory", () => {
       expect(instructions).not.toContain(".fusion/memory/MEMORY.md");
       expect(instructions).toContain("memory_search");
       expect(instructions).toContain("memory_get");
+      expect(instructions).toContain("fn_memory_append");
+      expect(instructions).toContain("Do **not** write memory files directly");
     });
 
     it("QMD triage instructions completeness - contains consult guidance", () => {

packages/core/src/__tests__/store-test-helpers.ts

@@ -52,7 +52,9 @@ export function createTaskStoreTestHarness() {
     afterEach: async () => {
       vi.useRealTimers();
       store.stopWatching();
-      await new Promise<void>((resolve) => process.nextTick(resolve));
+      // Yield one microtask tick without relying on process.nextTick,
+      // which can be faked in timer-heavy suites and hang teardown.
+      await Promise.resolve();
       store.close();
       await rm(rootDir, { recursive: true, force: true, maxRetries: 5, retryDelay: 50 });
       await rm(globalDir, { recursive: true, force: true, maxRetries: 5, retryDelay: 50 });

packages/core/src/project-memory.ts

@@ -374,6 +374,10 @@ This project has OpenClaw-style memory files:
 2. Use \`fn_memory_get\` only for specific memory files/line ranges returned by search
 3. Incorporate relevant learnings into your specification — reference actual patterns, constraints, and conventions documented there
 
+**Memory write contract for planning agents:**
+- If you need to save durable planning context, use \`fn_memory_append\` (choose scope/layer intentionally)
+- Do **not** write \`.fusion/memory/MEMORY.md\`, \`.fusion/memory/YYYY-MM-DD.md\`, or any other memory files directly when \`fn_memory_append\` is available
+
 Do not read all memory directly by default. If memory is irrelevant, skip it.
 `;
   }
@@ -389,6 +393,10 @@ This project has a memory system that stores durable project learnings.
 2. Use \`fn_memory_get\` only for specific memory files/line ranges returned by search
 3. Incorporate useful learnings into your specification
 
+**Memory write contract for planning agents:**
+- If you need to save durable planning context, use \`fn_memory_append\` (choose scope/layer intentionally)
+- Do **not** write memory files directly when \`fn_memory_append\` is available
+
 **If the memory contains useful context for this task, reference it in the specification.**
 `;
 }

packages/engine/src/__tests__/triage.test.ts

@@ -418,6 +418,9 @@ describe("buildSpecificationPrompt", () => {
       );
       expect(prompt).toContain("## Project Memory");
       expect(prompt).toContain(".fusion/memory/");
+      expect(prompt).toContain("fn_memory_append");
+      expect(prompt).toContain("Do **not** write");
+      expect(prompt).toContain("or any other memory files directly");
     });
 
     it("includes read-only wording for readonly backend without write directives", () => {
@@ -462,6 +465,8 @@ describe("buildSpecificationPrompt", () => {
       expect(prompt).not.toContain(".fusion/memory/");
       expect(prompt).toContain("fn_memory_search");
       expect(prompt).toContain("fn_memory_get");
+      expect(prompt).toContain("fn_memory_append");
+      expect(prompt).toContain("Do **not** write memory files directly");
     });
 
     it("QMD prompt has actionable memory instructions", () => {