Add plugin framework and settings UI

server/src/__tests__/plugin-worker-manager.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it } from "vitest";
+import { appendStderrExcerpt, formatWorkerFailureMessage } from "../services/plugin-worker-manager.js";
+
+describe("plugin-worker-manager stderr failure context", () => {
+  it("appends worker stderr context to failure messages", () => {
+    expect(
+      formatWorkerFailureMessage(
+        "Worker process exited (code=1, signal=null)",
+        "TypeError: Unknown file extension \".ts\"",
+      ),
+    ).toBe(
+      "Worker process exited (code=1, signal=null)\n\nWorker stderr:\nTypeError: Unknown file extension \".ts\"",
+    );
+  });
+
+  it("does not duplicate stderr that is already present", () => {
+    const message = [
+      "Worker process exited (code=1, signal=null)",
+      "",
+      "Worker stderr:",
+      "TypeError: Unknown file extension \".ts\"",
+    ].join("\n");
+
+    expect(
+      formatWorkerFailureMessage(message, "TypeError: Unknown file extension \".ts\""),
+    ).toBe(message);
+  });
+
+  it("keeps only the latest stderr excerpt", () => {
+    let excerpt = "";
+    excerpt = appendStderrExcerpt(excerpt, "first line");
+    excerpt = appendStderrExcerpt(excerpt, "second line");
+
+    expect(excerpt).toContain("first line");
+    expect(excerpt).toContain("second line");
+
+    excerpt = appendStderrExcerpt(excerpt, "x".repeat(9_000));
+
+    expect(excerpt).not.toContain("first line");
+    expect(excerpt).not.toContain("second line");
+    expect(excerpt.length).toBeLessThanOrEqual(8_000);
+  });
+});