feat(HAI-096): add task pause/unpause functionality

- Add paused field to Task data model and store with pauseTask method
- Update triage, scheduler, and executor to respect paused flag and terminate paused tasks
- Add REST API endpoints and CLI commands for pause/unpause operations
- Add dashboard UI visual indicator and toggle for paused state
- Update README with pause/unpause CLI command documentation

packages/cli/src/bin.ts

@@ -39,7 +39,7 @@ if (isBunBinary) {
 
 // Dynamic imports so the pi-coding-agent config module sees PI_PACKAGE_DIR
 const { runDashboard } = await import("./commands/dashboard.js");
-const { runTaskCreate, runTaskList, runTaskMove, runTaskMerge, runTaskUpdate, runTaskLog, runTaskShow, runTaskAttach } = await import("./commands/task.js");
+const { runTaskCreate, runTaskList, runTaskMove, runTaskMerge, runTaskUpdate, runTaskLog, runTaskShow, runTaskAttach, runTaskPause, runTaskUnpause } = await import("./commands/task.js");
 
 const HELP = `
 hai — AI-orchestrated task board
@@ -54,6 +54,8 @@ Usage:
   hai task log <id> <message>          Add a log entry
   hai task merge <id>                  Merge an in-review task and close it
   hai task attach <id> <file>          Attach a file to a task
+  hai task pause <id>                  Pause a task (stops all automation)
+  hai task unpause <id>                Unpause a task (resumes automation)
 
 Options:
   --port, -p <port>          Dashboard port (default: 4040)
@@ -161,6 +163,18 @@ async function main() {
             await runTaskAttach(id, file);
             break;
           }
+          case "pause": {
+            const id = args[2];
+            if (!id) { console.error("Usage: hai task pause <id>"); process.exit(1); }
+            await runTaskPause(id);
+            break;
+          }
+          case "unpause": {
+            const id = args[2];
+            if (!id) { console.error("Usage: hai task unpause <id>"); process.exit(1); }
+            await runTaskUnpause(id);
+            break;
+          }
           default:
             console.error(`Unknown subcommand: task ${subcommand || ""}`);
             console.log("Try: hai task create | list | move");

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

@@ -140,3 +140,80 @@ describe("runDashboard — WorktreePool wiring", () => {
     expect(executorPool).toBe(mergerPool);
   });
 });
+
+describe("runDashboard — auto-merge pause exclusion", () => {
+  let mockStore: ReturnType<typeof makeMockStore>;
+
+  beforeEach(async () => {
+    capturedExecutorOpts = undefined;
+    vi.clearAllMocks();
+    mockStore = makeMockStore();
+    const { TaskStore } = await import("@hai/core");
+    (TaskStore as ReturnType<typeof vi.fn>).mockImplementation(() => mockStore);
+    const engine = await import("@hai/engine");
+    (engine.aiMergeTask as ReturnType<typeof vi.fn>).mockImplementation(() =>
+      Promise.resolve({ merged: true }),
+    );
+    (engine.TaskExecutor as unknown as ReturnType<typeof vi.fn>).mockImplementation(
+      (_store: unknown, _cwd: unknown, opts: unknown) => {
+        capturedExecutorOpts = opts as Record<string, unknown>;
+        return { resumeOrphaned: vi.fn().mockResolvedValue(undefined) };
+      },
+    );
+  });
+
+  it("does not enqueue paused in-review tasks for auto-merge on task:moved", async () => {
+    mockStore.getSettings.mockResolvedValue({
+      maxConcurrent: 1,
+      maxWorktrees: 2,
+      autoMerge: true,
+      pollIntervalMs: 60_000,
+    });
+
+    await runDashboard(0, { engine: true, open: false });
+
+    const { aiMergeTask } = await import("@hai/engine");
+
+    // Emit task:moved with a paused task
+    mockStore.emit("task:moved", {
+      task: { id: "HAI-PAUSED", column: "in-review", paused: true },
+      from: "in-progress",
+      to: "in-review",
+    });
+
+    // Give async handlers time to process
+    await new Promise((r) => setTimeout(r, 50));
+
+    expect(aiMergeTask).not.toHaveBeenCalled();
+  });
+
+  it("does not enqueue paused in-review tasks during startup sweep", async () => {
+    mockStore.getSettings.mockResolvedValue({
+      maxConcurrent: 1,
+      maxWorktrees: 2,
+      autoMerge: true,
+      pollIntervalMs: 60_000,
+    });
+    mockStore.listTasks.mockResolvedValue([
+      { id: "HAI-PAUSED", column: "in-review", paused: true },
+      { id: "HAI-ACTIVE", column: "in-review", paused: false },
+    ]);
+
+    const { aiMergeTask } = await import("@hai/engine");
+    // Reset after import
+    (aiMergeTask as ReturnType<typeof vi.fn>).mockImplementation(() =>
+      Promise.resolve({ merged: true }),
+    );
+
+    await runDashboard(0, { engine: true, open: false });
+
+    // Give async handlers time to process
+    await new Promise((r) => setTimeout(r, 50));
+
+    // Only the non-paused task should be enqueued
+    const mergedIds = (aiMergeTask as ReturnType<typeof vi.fn>).mock.calls.map(
+      (call: any[]) => call[2],
+    );
+    expect(mergedIds).not.toContain("HAI-PAUSED");
+  });
+});

packages/cli/src/commands/dashboard.ts

@@ -96,9 +96,9 @@ export async function runDashboard(port: number, opts: { engine?: boolean; open?
             console.log(`[auto-merge] Skipping ${taskId} — autoMerge disabled`);
             continue;
           }
-          // Verify the task is still in-review (it may have been manually moved)
+          // Verify the task is still in-review and not paused
           const task = await store.getTask(taskId);
-          if (task.column !== "in-review") {
+          if (task.column !== "in-review" || task.paused) {
             continue;
           }
           console.log(`[auto-merge] Merging ${taskId}...`);
@@ -123,6 +123,7 @@ export async function runDashboard(port: number, opts: { engine?: boolean; open?
   // enqueue it for serialized merge processing.
   store.on("task:moved", async ({ task, to }) => {
     if (to !== "in-review") return;
+    if (task.paused) return;
     try {
       const settings = await store.getSettings();
       if (!settings.autoMerge) return;
@@ -177,7 +178,7 @@ export async function runDashboard(port: number, opts: { engine?: boolean; open?
     // ── Startup sweep: enqueue any tasks already in "in-review" ───────
     if (settings.autoMerge) {
       const existing = await store.listTasks();
-      const inReview = existing.filter((t) => t.column === "in-review");
+      const inReview = existing.filter((t) => t.column === "in-review" && !t.paused);
       if (inReview.length > 0) {
         console.log(
           `[auto-merge] Startup sweep: enqueueing ${inReview.length} in-review task(s)`,
@@ -203,7 +204,7 @@ export async function runDashboard(port: number, opts: { engine?: boolean; open?
           if (s.autoMerge) {
             const tasks = await store.listTasks();
             for (const t of tasks) {
-              if (t.column === "in-review") {
+              if (t.column === "in-review" && !t.paused) {
                 enqueueMerge(t.id);
               }
             }

packages/cli/src/commands/task.ts

@@ -250,6 +250,24 @@ export async function runTaskAttach(id: string, filePath: string) {
   console.log();
 }
 
+export async function runTaskPause(id: string) {
+  const store = await getStore();
+  const task = await store.pauseTask(id, true);
+
+  console.log();
+  console.log(`  ✓ Paused ${task.id}`);
+  console.log();
+}
+
+export async function runTaskUnpause(id: string) {
+  const store = await getStore();
+  const task = await store.pauseTask(id, false);
+
+  console.log();
+  console.log(`  ✓ Unpaused ${task.id}`);
+  console.log();
+}
+
 export async function runTaskMove(id: string, column: string) {
   if (!COLUMNS.includes(column as Column)) {
     console.error(`Invalid column: ${column}`);