refactor(FN-1615): convert CLI execSync to async exec

- Replace execSync with promisified execAsync in init.ts detectProjectName() for non-blocking git remote lookups
- Replace execSync with promisified execAsync in task-lifecycle.ts cleanupMergedTaskArtifacts() for non-blocking git worktree/branch cleanup
- Add 30s timeout to git operations to prevent indefinite hangs
- Update test mocks to support both callback-style and promise-style exec usage

packages/cli/src/commands/dashboard.test.ts

@@ -163,7 +163,14 @@ const {
   mockGetPrMergeStatus,
   mockMergePr,
 } = vi.hoisted(() => ({
-  mockExec: vi.fn((_command: string, callback?: () => void) => callback?.()),
+  mockExec: vi.fn((_command: string, _options?: any, callback?: (err: null, stdout: string, stderr: string) => void) => {
+    // Handle both callback-style (original exec) and promise-style (promisified execAsync)
+    if (typeof callback === "function") {
+      callback(null, "", "");
+    }
+    // Return resolved promise for promisified usage
+    return Promise.resolve({ stdout: "", stderr: "" });
+  }),
   mockExecSync: vi.fn(() => ""),
   mockFindPrForBranch: vi.fn(),
   mockCreatePr: vi.fn(),
@@ -547,8 +554,9 @@ describe("processPullRequestMergeTask", () => {
     expect(result).toBe("merged");
     expect(mockMergePr).toHaveBeenCalledWith({ number: 42, method: "squash" });
     expect(store.moveTask).toHaveBeenCalledWith("FN-093", "done");
-    expect(mockExecSync).toHaveBeenCalledWith('git worktree remove "/tmp/kb-093" --force', expect.any(Object));
-    expect(mockExecSync).toHaveBeenCalledWith('git branch -d "fusion/fn-093"', expect.any(Object));
+    // Check that exec was called with the expected commands (options object and callback may follow)
+    expect(mockExec.mock.calls.some((call) => call[0] === 'git worktree remove "/tmp/kb-093" --force')).toBe(true);
+    expect(mockExec.mock.calls.some((call) => call[0] === 'git branch -d "fusion/fn-093"')).toBe(true);
   });
 
   it("does not merge when required checks or reviews are blocking", async () => {

packages/cli/src/commands/init.ts

@@ -11,7 +11,9 @@
 import { existsSync, mkdirSync, writeFileSync } from "node:fs";
 import { join, resolve, basename } from "node:path";
 import { homedir } from "node:os";
-import { execSync } from "node:child_process";
+import { exec } from "node:child_process";
+import { promisify } from "node:util";
+const execAsync = promisify(exec);
 import { CentralCore } from "@fusion/core";
 import { resolveGlobalDir } from "@fusion/core";
 
@@ -53,7 +55,7 @@ export async function runInit(options: InitOptions = {}): Promise<void> {
     }
 
     // Has .fusion/ but not registered - offer to register
-    const projectName = options.name ?? detectProjectName(cwd);
+    const projectName = options.name ?? await detectProjectName(cwd);
     console.log(`⚠ Project directory exists but not registered.`);
     console.log(`  Run: fn project add ${projectName} ${cwd}`);
     console.log(`  Or: rm -rf ${fusionDir} && fn init`);
@@ -62,7 +64,7 @@ export async function runInit(options: InitOptions = {}): Promise<void> {
   }
 
   // Get or generate project name
-  const projectName = options.name ?? detectProjectName(cwd);
+  const projectName = options.name ?? await detectProjectName(cwd);
 
   console.log(`Initializing fn project: "${projectName}"`);
   console.log(`  Path: ${cwd}`);
@@ -133,18 +135,19 @@ export async function runInit(options: InitOptions = {}): Promise<void> {
 /**
  * Detect a project name from git remote or directory name.
  */
-function detectProjectName(dir: string): string {
+async function detectProjectName(dir: string): Promise<string> {
   // Try git remote first
   try {
-    const remoteUrl = execSync("git remote get-url origin 2>/dev/null", {
+    const { stdout: remoteUrl } = await execAsync("git remote get-url origin", {
       cwd: dir,
-      encoding: "utf-8",
-    }).trim();
+      timeout: 10_000,
+    });
 
-    if (remoteUrl) {
+    const trimmed = remoteUrl.trim();
+    if (trimmed) {
       // Extract repo name from URL
       // Handles: https://github.com/user/repo.git, git@github.com:user/repo.git
-      const match = remoteUrl.match(/[:/]([^/]+)\/([^/.]+?)(?:\.git)?$/);
+      const match = trimmed.match(/[:/]([^/]+)\/([^/.]+?)(?:\.git)?$/);
       if (match) {
         return match[2];
       }

packages/cli/src/commands/task-lifecycle.ts

@@ -13,7 +13,9 @@
  * - Full PR lifecycle orchestration (create → status check → merge)
  */
 
-import { execSync } from "node:child_process";
+import { exec } from "node:child_process";
+import { promisify } from "node:util";
+const execAsync = promisify(exec);
 import type { TaskStore } from "@fusion/core";
 import type { Settings, TaskDetail, PrInfo } from "@fusion/core";
 
@@ -75,14 +77,14 @@ function buildPullRequestBody(task: Pick<TaskDetail, "id" | "description">): str
  * Clean up worktree and branch artifacts after a successful merge.
  * Both operations are best-effort; errors are logged but don't propagate.
  */
-export function cleanupMergedTaskArtifacts(cwd: string, task: Pick<TaskDetail, "id" | "worktree">): void {
+export async function cleanupMergedTaskArtifacts(cwd: string, task: Pick<TaskDetail, "id" | "worktree">): Promise<void> {
   const branch = getTaskBranchName(task.id);
 
   if (task.worktree) {
     try {
-      execSync(`git worktree remove "${task.worktree}" --force`, {
+      await execAsync(`git worktree remove "${task.worktree}" --force`, {
         cwd,
-        stdio: "pipe",
+        timeout: 30_000,
       });
     } catch {
       // Best-effort cleanup — worktree may already be gone.
@@ -90,15 +92,15 @@ export function cleanupMergedTaskArtifacts(cwd: string, task: Pick<TaskDetail, "
   }
 
   try {
-    execSync(`git branch -d "${branch}"`, {
+    await execAsync(`git branch -d "${branch}"`, {
       cwd,
-      stdio: "pipe",
+      timeout: 30_000,
     });
   } catch {
     try {
-      execSync(`git branch -D "${branch}"`, {
+      await execAsync(`git branch -D "${branch}"`, {
         cwd,
-        stdio: "pipe",
+        timeout: 30_000,
       });
     } catch {
       // Best-effort cleanup — branch may already be gone.
@@ -186,7 +188,7 @@ export async function processPullRequestMergeTask(
   await store.updatePrInfo(task.id, refreshedPrInfo);
 
   if (mergeStatus.prInfo.status === "merged") {
-    cleanupMergedTaskArtifacts(cwd, task);
+    await cleanupMergedTaskArtifacts(cwd, task);
     await store.moveTask(task.id, "done");
     await store.updateTask(task.id, { status: null, mergeRetries: 0 });
     await store.logEntry(task.id, "Pull request merged", `PR #${prInfo.number}: ${prInfo.url}`);
@@ -205,7 +207,7 @@ export async function processPullRequestMergeTask(
   await store.updateTask(task.id, { status: "merging-pr" });
   const mergedPr = await github.mergePr({ number: prInfo.number, method: "squash" });
   await store.updatePrInfo(task.id, { ...mergedPr, lastCheckedAt: new Date().toISOString() });
-  cleanupMergedTaskArtifacts(cwd, task);
+  await cleanupMergedTaskArtifacts(cwd, task);
   await store.moveTask(task.id, "done");
   await store.updateTask(task.id, { status: null, mergeRetries: 0 });
   await store.logEntry(task.id, "Pull request merged", `PR #${mergedPr.number}: ${mergedPr.url}`);