fix: remove pgvector dependency from AI knowledge retrieval

modules/ai/server/knowledge.test.ts

@@ -130,7 +130,7 @@ type RetrievedChunkRow = {
   title: string;
   category: string;
   content: string;
-  distance: number;
+  embedding: number[];
 };
 
 type KnowledgeDatabaseFake = {
@@ -325,7 +325,7 @@ class SelectBuilder implements PromiseLike<SelectRow[]> {
           title: chunk.sourceTitle,
           category: chunk.sourceCategory,
           content: chunk.content,
-          distance: 0.1 + rows.length * 0.1,
+          embedding: chunk.embedding,
         });
       }
     }
@@ -407,6 +407,31 @@ describe("AI knowledge service", () => {
     expect(embeddingMocks.embedDocuments).toHaveBeenCalledWith(["night fall risk"]);
   });
 
+  it("orders retrieved chunks by cosine similarity after scope filtering", async () => {
+    const weakEntry = createEntry({ id: "entry-weak", title: "Weak guidance" });
+    const strongEntry = createEntry({ id: "entry-strong", title: "Strong guidance" });
+    useDatabase(createDatabaseFake({
+      entries: [weakEntry, strongEntry],
+      chunks: [
+        createChunk(weakEntry, { embedding: [0, 1, 0] }),
+        createChunk(strongEntry, { embedding: [1, 0, 0] }),
+      ],
+    }));
+    embeddingMocks.embedDocuments.mockResolvedValueOnce([[1, 0, 0]]);
+
+    const result = await retrieveKnowledge("org-1", "night fall risk", { limit: 2 });
+
+    expect(result).toEqual({
+      success: true,
+      data: {
+        results: [
+          expect.objectContaining({ entryId: "entry-strong", score: 1 }),
+          expect.objectContaining({ entryId: "entry-weak", score: 0 }),
+        ],
+      },
+    });
+  });
+
   it("requires platform management permission before mutating platform knowledge", async () => {
     const existingPlatformEntry = createEntry({ id: "entry-platform", scope: "platform", organizationId: null });
     useDatabase(createDatabaseFake({ entries: [existingPlatformEntry] }));