fix(eve): scope forget, persist capture idempotency, and fail closed

Review findings: delete was not partitioned by scope.key, capture
replay after restart could double-write, and Mem0 errors were swallowed
as empty recall.

Co-authored-by: Cursor <cursoragent@cursor.com>

integrations/eve/tests/recall.test.ts

@@ -3,11 +3,12 @@ import { formatRecallMessages, recallMemories } from "../src/recall.js";
 import { createFakeStore } from "./helpers.js";
 
 describe("formatRecallMessages", () => {
-  it("drops empty memories", () => {
+  it("drops empty memories and empty ids", () => {
     expect(
       formatRecallMessages([
         { id: "1", memory: " likes tea " },
         { id: "2", memory: "   " },
+        { id: "  ", memory: "kept text" },
       ]),
     ).toEqual([{ id: "1", content: "likes tea" }]);
   });
@@ -20,13 +21,19 @@ describe("recallMemories", () => {
       store,
       scopeKey: "scope_abc",
       query: "What does the user drink?",
-      topK: 5,
-      threshold: 0.1,
-      rerank: false,
+      topK: 3,
+      threshold: 0.5,
+      rerank: true,
     });
 
     expect(store.searched).toEqual([
-      { query: "What does the user drink?", userId: "scope_abc" },
+      {
+        query: "What does the user drink?",
+        userId: "scope_abc",
+        topK: 3,
+        threshold: 0.5,
+        rerank: true,
+      },
     ]);
     expect(result).toEqual({
       messages: [{ id: "mem_1", content: "User likes tea" }],
@@ -47,4 +54,18 @@ describe("recallMemories", () => {
     ).resolves.toBeNull();
     expect(store.searched).toEqual([]);
   });
+
+  it("returns null when search has no usable hits", async () => {
+    const store = createFakeStore([{ id: "  ", memory: "   " }]);
+    await expect(
+      recallMemories({
+        store,
+        scopeKey: "scope_abc",
+        query: "tea",
+        topK: 5,
+        threshold: 0.1,
+        rerank: false,
+      }),
+    ).resolves.toBeNull();
+  });
 });