Add MSW infrastructure: handlers, fixtures, request-log, and Vitest setup

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/mocks/handlers/discover.js

@@ -0,0 +1,24 @@
+/**
+ * MSW handlers for process discovery (map) endpoints.
+ * @module mocks/handlers/discover
+ */
+import { http, HttpResponse } from "msw";
+import discoverData from "../fixtures/discover.json";
+import { captureRequest } from "../request-log.js";
+
+export const discoverHandlers = [
+  http.get("/api/logs/:id/discover", ({ params }) => {
+    captureRequest("GET", `/api/logs/${params.id}/discover`);
+    return HttpResponse.json(discoverData);
+  }),
+
+  http.get("/api/filters/:id/discover", ({ params }) => {
+    captureRequest("GET", `/api/filters/${params.id}/discover`);
+    return HttpResponse.json(discoverData);
+  }),
+
+  http.get("/api/temp-filters/:id/discover", ({ params }) => {
+    captureRequest("GET", `/api/temp-filters/${params.id}/discover`);
+    return HttpResponse.json(discoverData);
+  }),
+];