perf(web): stream dashboard tile events

apps/web/src/server/routes/dashboard.test.ts

@@ -3,6 +3,7 @@ import { dimensionLabDashboardFixture } from "$lib/dashboard-seed/dimensionlab";
 import {
   createDashboardTileCache,
   dashboardTileCacheKey,
+  handleDashboardEventsRoute,
   handleDashboardTilesRoute,
   handleDashboardTileRoute,
   loadDashboardResponse,
@@ -605,6 +606,45 @@ describe("dashboard API route", () => {
     });
   });
 
+  test("streams ready dashboard tile events", async () => {
+    const controller = new AbortController();
+    const response = await handleDashboardEventsRoute({
+      refreshSeedDocument: true,
+      seedIfEmpty: true,
+      signal: controller.signal,
+      tileCache: {
+        async resolve(key) {
+          controller.abort();
+          const tile = JSON.parse(key);
+
+          return {
+            cache: "miss",
+            coalesced: false,
+            response: {
+              state: "ready",
+              tile,
+              item: {
+                id: tile.id,
+                label: "Status",
+                severity: "ok",
+                value: "ok",
+              },
+            },
+          };
+        },
+      },
+    });
+
+    expect(response.headers.get("content-type")).toBe(
+      "text/event-stream; charset=utf-8",
+    );
+    expect(response.headers.get("cache-control")).toBe("no-cache");
+    const body = await response.text();
+    expect(body).toContain("event: dashboard-tile");
+    expect(body).toContain('"state":"ready"');
+    expect(body).toContain('"tile"');
+  });
+
   test("rejects invalid batch tile requests", async () => {
     const response = await handleDashboardTilesRoute(
       new Request("https://example.test/api/dashboard/tiles", {