feat(FN-3876): add GitHub tracking test coverage across settings, issues, s

Adds comprehensive test coverage for GitHub tracking across four areas: settings inheritance, issue creation, status sync transitions, and unlink sync regression — spanning 280 lines of new tests across four test files with minimal store.ts adjustment.

Fusion-Task-Id: FN-3876

packages/dashboard/src/__tests__/github-tracking-unlink.test.ts

@@ -0,0 +1,127 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { mkdtempSync } from "node:fs";
+import { rm } from "node:fs/promises";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+import { TaskStore } from "@fusion/core";
+import { GitHubTrackingCommentService } from "../github-tracking-comments.js";
+import { GitHubTrackingStateService } from "../github-tracking-state.js";
+
+const { mockCommentOnIssue, mockSetIssueState, mockResolveGithubTrackingAuth } = vi.hoisted(() => ({
+  mockCommentOnIssue: vi.fn(),
+  mockSetIssueState: vi.fn(),
+  mockResolveGithubTrackingAuth: vi.fn(),
+}));
+
+vi.mock("../github.js", () => ({
+  GitHubClient: vi.fn().mockImplementation(() => ({
+    commentOnIssue: (...args: unknown[]) => mockCommentOnIssue(...args),
+    setIssueState: (...args: unknown[]) => mockSetIssueState(...args),
+  })),
+}));
+
+vi.mock("../github-auth.js", () => ({
+  resolveGithubTrackingAuth: (...args: unknown[]) => mockResolveGithubTrackingAuth(...args),
+}));
+
+function makeTmpDir(): string {
+  return mkdtempSync(join(tmpdir(), "kb-dashboard-github-tracking-unlink-test-"));
+}
+
+async function flushAsync(): Promise<void> {
+  await new Promise((resolve) => setTimeout(resolve, 0));
+}
+
+describe("github tracking unlink flow", () => {
+  let rootDir: string;
+  let globalDir: string;
+  let store: TaskStore;
+  let commentService: GitHubTrackingCommentService;
+  let stateService: GitHubTrackingStateService;
+
+  beforeEach(async () => {
+    vi.clearAllMocks();
+    mockResolveGithubTrackingAuth.mockReturnValue({ ok: true, auth: { mode: "token", token: "token" } });
+    rootDir = makeTmpDir();
+    globalDir = makeTmpDir();
+    store = new TaskStore(rootDir, globalDir, { inMemoryDb: true });
+    await store.init();
+    commentService = new GitHubTrackingCommentService(store);
+    stateService = new GitHubTrackingStateService(store);
+    commentService.start();
+    stateService.start();
+  });
+
+  afterEach(async () => {
+    commentService.stop();
+    stateService.stop();
+    await flushAsync();
+    store.close();
+    await rm(rootDir, { recursive: true, force: true });
+    await rm(globalDir, { recursive: true, force: true });
+  });
+
+  it("clears linked issue metadata on unlink while preserving toggle semantics", async () => {
+    const task = await store.createTask({
+      description: "unlink",
+      githubTracking: {
+        enabled: true,
+        repoOverride: "octocat/hello-world",
+      },
+    });
+
+    await store.linkGithubIssue(task.id, {
+      owner: "octocat",
+      repo: "hello-world",
+      number: 7,
+      url: "https://github.com/octocat/hello-world/issues/7",
+      createdAt: new Date().toISOString(),
+    });
+
+    const unlinked = await store.unlinkGithubIssue(task.id);
+    expect(unlinked.githubTracking?.issue).toBeUndefined();
+    expect(unlinked.githubTracking?.unlinkedAt).toBeTruthy();
+    expect(unlinked.githubTracking?.enabled).toBe(true);
+  });
+
+  it("stops all status-sync calls after unlink and does not mutate remote issue during unlink", async () => {
+    const task = await store.createTask({
+      description: "unlink sync",
+      githubTracking: { enabled: true },
+    });
+
+    await store.linkGithubIssue(task.id, {
+      owner: "octocat",
+      repo: "hello-world",
+      number: 9,
+      url: "https://github.com/octocat/hello-world/issues/9",
+      createdAt: new Date().toISOString(),
+    });
+
+    await store.moveTask(task.id, "todo");
+    await store.moveTask(task.id, "in-progress");
+    await store.moveTask(task.id, "done");
+    await flushAsync();
+
+    expect(mockCommentOnIssue).toHaveBeenCalled();
+    expect(mockSetIssueState).toHaveBeenCalled();
+
+    mockCommentOnIssue.mockClear();
+    mockSetIssueState.mockClear();
+
+    await store.unlinkGithubIssue(task.id);
+    await flushAsync();
+
+    // unlink is local-only: should not close/reopen/comment as a side-effect
+    expect(mockCommentOnIssue).not.toHaveBeenCalled();
+    expect(mockSetIssueState).not.toHaveBeenCalled();
+
+    await store.moveTask(task.id, "todo");
+    await store.moveTask(task.id, "in-progress");
+    await store.moveTask(task.id, "done");
+    await flushAsync();
+
+    expect(mockCommentOnIssue).not.toHaveBeenCalled();
+    expect(mockSetIssueState).not.toHaveBeenCalled();
+  });
+});