feat: add xai media providers

Add xAI image generation and text-to-speech provider support with docs, live tests, and guarded provider HTTP handling.\n\nThanks @KateWilkins.

test/image-generation.runtime.live.test.ts

@@ -79,6 +79,11 @@ const PROVIDER_CASES: LiveProviderCase[] = [
     pluginName: "Vydra Provider",
     providerId: "vydra",
   },
+  {
+    pluginId: "xai",
+    pluginName: "xAI Provider",
+    providerId: "xai",
+  },
 ]
   .filter((entry) => (providerFilter ? providerFilter.has(entry.providerId) : true))
   .toSorted((left, right) => left.providerId.localeCompare(right.providerId));

test/vitest-scoped-config.test.ts

@@ -59,6 +59,7 @@ import { createRuntimeConfigVitestConfig } from "./vitest/vitest.runtime-config.
 import { createScopedVitestConfig, resolveVitestIsolation } from "./vitest/vitest.scoped-config.ts";
 import { createSecretsVitestConfig } from "./vitest/vitest.secrets.config.ts";
 import { createSharedCoreVitestConfig } from "./vitest/vitest.shared-core.config.ts";
+import { sharedVitestConfig } from "./vitest/vitest.shared.config.ts";
 import { createTasksVitestConfig } from "./vitest/vitest.tasks.config.ts";
 import { createToolingVitestConfig } from "./vitest/vitest.tooling.config.ts";
 import { createTuiVitestConfig } from "./vitest/vitest.tui.config.ts";
@@ -321,7 +322,7 @@ describe("scoped vitest configs", () => {
   });
 
   it("keeps the broad agents lane on shared file parallelism", () => {
-    expect(defaultAgentsConfig.test?.fileParallelism).toBe(true);
+    expect(defaultAgentsConfig.test?.fileParallelism).toBe(sharedVitestConfig.test.fileParallelism);
   });
 
   it("keeps selected plugin-sdk and commands light lanes off the openclaw runtime setup", () => {