Add browser-based board CLI auth flow

Co-Authored-By: Paperclip <noreply@paperclip.ing>

cli/src/__tests__/board-auth.test.ts

@@ -0,0 +1,53 @@
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { describe, expect, it } from "vitest";
+import {
+  getStoredBoardCredential,
+  readBoardAuthStore,
+  removeStoredBoardCredential,
+  setStoredBoardCredential,
+} from "../client/board-auth.js";
+
+function createTempAuthPath(): string {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "paperclip-cli-auth-"));
+  return path.join(dir, "auth.json");
+}
+
+describe("board auth store", () => {
+  it("returns an empty store when the file does not exist", () => {
+    const authPath = createTempAuthPath();
+    expect(readBoardAuthStore(authPath)).toEqual({
+      version: 1,
+      credentials: {},
+    });
+  });
+
+  it("stores and retrieves credentials by normalized api base", () => {
+    const authPath = createTempAuthPath();
+    setStoredBoardCredential({
+      apiBase: "http://localhost:3100/",
+      token: "token-123",
+      userId: "user-1",
+      storePath: authPath,
+    });
+
+    expect(getStoredBoardCredential("http://localhost:3100", authPath)).toMatchObject({
+      apiBase: "http://localhost:3100",
+      token: "token-123",
+      userId: "user-1",
+    });
+  });
+
+  it("removes stored credentials", () => {
+    const authPath = createTempAuthPath();
+    setStoredBoardCredential({
+      apiBase: "http://localhost:3100",
+      token: "token-123",
+      storePath: authPath,
+    });
+
+    expect(removeStoredBoardCredential("http://localhost:3100", authPath)).toBe(true);
+    expect(getStoredBoardCredential("http://localhost:3100", authPath)).toBeNull();
+  });
+});