feat: AI-powered merge via pi agent

packages/dashboard/src/index.ts

@@ -1 +1 @@
-export { createServer } from "./server.js";
+export { createServer, type ServerOptions } from "./server.js";

packages/dashboard/src/routes.ts

@@ -1,8 +1,9 @@
 import { Router } from "express";
-import type { TaskStore, Column } from "@hai/core";
+import type { TaskStore, Column, MergeResult } from "@hai/core";
 import { COLUMNS } from "@hai/core";
+import type { ServerOptions } from "./server.js";
 
-export function createApiRoutes(store: TaskStore): Router {
+export function createApiRoutes(store: TaskStore, options?: ServerOptions): Router {
   const router = Router();
 
   // List all tasks
@@ -54,13 +55,15 @@ export function createApiRoutes(store: TaskStore): Router {
   });
 
   // Merge task (in-review → done, merges branch + cleans worktree)
+  // Uses AI merge handler if provided, falls back to store.mergeTask
   router.post("/tasks/:id/merge", async (req, res) => {
     try {
-      const result = await store.mergeTask(req.params.id);
+      const merge = options?.onMerge ?? ((id: string) => store.mergeTask(id));
+      const result = await merge(req.params.id);
       res.json(result);
     } catch (err: any) {
       const status = err.message.includes("Cannot merge") ? 400
-        : err.message.includes("Merge conflict") ? 409
+        : err.message.includes("conflict") ? 409
         : 500;
       res.status(status).json({ error: err.message });
     }

packages/dashboard/src/server.ts

@@ -2,13 +2,18 @@ import express from "express";
 import { join, dirname } from "node:path";
 import { existsSync } from "node:fs";
 import { fileURLToPath } from "node:url";
-import type { TaskStore } from "@hai/core";
+import type { TaskStore, MergeResult } from "@hai/core";
 import { createApiRoutes } from "./routes.js";
 import { createSSE } from "./sse.js";
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
-export function createServer(store: TaskStore): ReturnType<typeof express> {
+export interface ServerOptions {
+  /** Custom merge handler — when provided, used instead of store.mergeTask */
+  onMerge?: (taskId: string) => Promise<MergeResult>;
+}
+
+export function createServer(store: TaskStore, options?: ServerOptions): ReturnType<typeof express> {
   const app = express();
 
   app.use(express.json());
@@ -25,7 +30,7 @@ export function createServer(store: TaskStore): ReturnType<typeof express> {
   app.get("/api/events", createSSE(store));
 
   // REST API
-  app.use("/api", createApiRoutes(store));
+  app.use("/api", createApiRoutes(store, options));
 
   // SPA fallback
   app.get("/{*splat}", (_req, res) => {