feat(headroom): add extras detection and install UI (#2403)

- add Headroom extras status + install endpoints
- show Headroom version + code/ml extras in Token Saver UI
- fix Windows interpreter selection to read from env with headroom-ai

tests/unit/headroom-detect.test.js

@@ -2,21 +2,93 @@ import { describe, it, expect, vi, afterEach } from "vitest";
 
 const mocks = vi.hoisted(() => ({
   execSync: vi.fn(() => { throw new Error("not found"); }),
+  execFile: vi.fn(() => ({ toString: () => "[object Object]" })),
+  execFileSync: vi.fn(() => Buffer.from(JSON.stringify([
+    { name: "headroom-ai", version: "0.26.0" },
+    { name: "tree-sitter", version: "0.25.0" },
+  ]))),
 }));
 
 vi.mock("child_process", () => ({
   execSync: mocks.execSync,
+  execFile: mocks.execFile,
+  execFileSync: mocks.execFileSync,
 }));
 
-import { getHeadroomStatus, isLoopbackHeadroomUrl } from "../../src/lib/headroom/detect.js";
+import { findPython310, getHeadroomStatus, getInstalledHeadroomExtras, isLoopbackHeadroomUrl } from "../../src/lib/headroom/detect.js";
 
 afterEach(() => {
   vi.clearAllMocks();
 });
 
 describe("headroom detect", () => {
+  it("detects installed headroom version and extras from pip list", () => {
+    const result = getInstalledHeadroomExtras("python3");
+
+    expect(mocks.execFileSync).toHaveBeenCalledWith(
+      "python3",
+      ["-m", "pip", "list", "--format=json", "--disable-pip-version-check"],
+      expect.objectContaining({ windowsHide: true, timeout: 8000 }),
+    );
+    expect(result).toEqual({
+      installed: true,
+      version: "0.26.0",
+      extras: { code: true, ml: false },
+    });
+  });
+
+  it("prefers the interpreter that actually has headroom-ai installed", () => {
+    mocks.execSync.mockImplementation((cmd) => {
+      if (String(cmd).includes("where") || String(cmd).includes("which")) return Buffer.from("C:/Python/Scripts/headroom.exe\n");
+      if (String(cmd).includes("python3 --version")) return Buffer.from("Python 3.13.0\n");
+      if (String(cmd).includes("python --version")) return Buffer.from("Python 3.13.0\n");
+      throw new Error("unexpected execSync");
+    });
+    mocks.execFileSync.mockImplementation((py, args) => {
+      if (py === "python3" && args.join(" ") === "-m pip show headroom-ai") throw new Error("not installed in python3");
+      if (py === "python" && args.join(" ") === "-m pip show headroom-ai") return Buffer.from("Name: headroom-ai\nVersion: 0.26.0\n");
+      if (py === "python" && args.join(" ").startsWith("-m pip list ")) return Buffer.from(JSON.stringify([
+        { name: "headroom-ai", version: "0.26.0" },
+        { name: "tree-sitter", version: "0.25.0" },
+      ]));
+      throw new Error(`unexpected execFileSync: ${py} ${args.join(" ")}`);
+    });
+
+    expect(findPython310()).toBe("python");
+  });
+
+  it("keeps top-level installed flag true when extras are readable", async () => {
+    global.fetch = vi.fn(async () => new Response("ok", { status: 200 }));
+    mocks.execSync.mockImplementation((cmd) => {
+      if (String(cmd).includes("where") || String(cmd).includes("which")) return Buffer.from("C:/Python/Scripts/headroom.exe\n");
+      if (String(cmd).includes("python3 --version")) return Buffer.from("Python 3.13.0\n");
+      if (String(cmd).includes("python --version")) return Buffer.from("Python 3.13.0\n");
+      throw new Error("unexpected execSync");
+    });
+    mocks.execFileSync.mockImplementation((py, args) => {
+      if (py === "python3" && args.join(" ") === "-m pip show headroom-ai") throw new Error("not installed in python3");
+      if (py === "python" && args.join(" ") === "-m pip show headroom-ai") return Buffer.from("Name: headroom-ai\nVersion: 0.26.0\n");
+      if (py === "python" && args.join(" ").startsWith("-m pip list ")) return Buffer.from(JSON.stringify([
+        { name: "headroom-ai", version: "0.26.0" },
+        { name: "tree-sitter", version: "0.25.0" },
+      ]));
+      throw new Error(`unexpected execFileSync: ${py} ${args.join(" ")}`);
+    });
+
+    const status = await getHeadroomStatus("http://localhost:8787");
+
+    expect(status.installed).toBe(true);
+    expect(status.version).toBe("0.26.0");
+    expect(status.extras).toEqual({ code: true, ml: false });
+  });
+
   it("treats a reachable external proxy as running without local CLI", async () => {
     global.fetch = vi.fn(async () => new Response("ok", { status: 200 }));
+    mocks.execSync.mockImplementation((cmd) => {
+      if (String(cmd).includes("where") || String(cmd).includes("which")) throw new Error("not found");
+      throw new Error("unexpected execSync");
+    });
+    mocks.execFileSync.mockImplementation(() => { throw new Error("pip unavailable"); });
 
     const status = await getHeadroomStatus("http://headroom:8787");