feat(FN-3573): harden plugin setup sync and test-isolation handling

- Add plugin setup API coverage for migration and sync edge cases
- Expand plugin route tests and implementation safeguards for setup state handling
- Update legacy API glue to align plugin setup responses with route behavior
- Keep test-isolation runtime ignore handling compatible with live app activity

Fusion-Task-Id: FN-3573

packages/dashboard/app/api/__tests__/plugin-setup-api.test.ts

@@ -0,0 +1,60 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { fetchPluginSetupStatus, installPluginSetup } from "../../api";
+
+describe("plugin setup API helpers", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("fetchPluginSetupStatus calls setup-status endpoint with encoded id", async () => {
+    const fetchMock = vi.spyOn(globalThis, "fetch").mockResolvedValue(
+      new Response(JSON.stringify({ hasSetup: true, status: "installed" }), {
+        status: 200,
+        headers: { "content-type": "application/json" },
+      }),
+    );
+
+    const result = await fetchPluginSetupStatus("plugin/id");
+
+    expect(result).toEqual({ hasSetup: true, status: "installed" });
+    expect(fetchMock).toHaveBeenCalledWith(
+      "/api/plugins/plugin%2Fid/setup-status",
+      expect.objectContaining({
+        headers: expect.objectContaining({ "Content-Type": "application/json" }),
+      }),
+    );
+  });
+
+  it("fetchPluginSetupStatus includes projectId query parameter", async () => {
+    const fetchMock = vi.spyOn(globalThis, "fetch").mockResolvedValue(
+      new Response(JSON.stringify({ hasSetup: false }), {
+        status: 200,
+        headers: { "content-type": "application/json" },
+      }),
+    );
+
+    await fetchPluginSetupStatus("my-plugin", "project/one");
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      "/api/plugins/my-plugin/setup-status?projectId=project%2Fone",
+      expect.any(Object),
+    );
+  });
+
+  it("installPluginSetup posts to setup install endpoint and supports project scope", async () => {
+    const fetchMock = vi.spyOn(globalThis, "fetch").mockResolvedValue(
+      new Response(JSON.stringify({ success: true }), {
+        status: 200,
+        headers: { "content-type": "application/json" },
+      }),
+    );
+
+    const result = await installPluginSetup("my plugin", "proj");
+
+    expect(result).toEqual({ success: true });
+    expect(fetchMock).toHaveBeenCalledWith(
+      "/api/plugins/my%20plugin/setup/install?projectId=proj",
+      expect.objectContaining({ method: "POST" }),
+    );
+  });
+});

packages/dashboard/app/api/legacy.ts

@@ -18,6 +18,7 @@ import type {
   WorkflowStepInput,
   WorkflowStepResult,
   PluginInstallation,
+  PluginSetupCheckResult,
   PluginUiSlotDefinition,
   PluginUiContributionDefinition,
   PluginDashboardViewDefinition,
@@ -7763,6 +7764,23 @@ export async function updatePluginSettings(
   });
 }
 
+export type PluginSetupStatusResponse =
+  | { hasSetup: false }
+  | { hasSetup: false; status: Extract<PluginSetupCheckResult, { status: "error" }> }
+  | ({ hasSetup: true } & PluginSetupCheckResult);
+
+/** Fetch plugin setup status */
+export async function fetchPluginSetupStatus(id: string, projectId?: string): Promise<PluginSetupStatusResponse> {
+  return api<PluginSetupStatusResponse>(withProjectId(`/plugins/${encodeURIComponent(id)}/setup-status`, projectId));
+}
+
+/** Trigger plugin setup install hook */
+export async function installPluginSetup(id: string, projectId?: string): Promise<{ success: boolean; error?: string }> {
+  return api<{ success: boolean; error?: string }>(withProjectId(`/plugins/${encodeURIComponent(id)}/setup/install`, projectId), {
+    method: "POST",
+  });
+}
+
 /** Reload a running plugin with updated code */
 export async function reloadPlugin(id: string, projectId?: string): Promise<PluginInstallation> {
   return api<PluginInstallation>(withProjectId(`/plugins/${encodeURIComponent(id)}/reload`, projectId), {