feat(HAI-078): add configurable task prefix to settings

- Add taskPrefix field to Settings type and use it in allocateId
- Update store listTasks and handleFsChange to support any task prefix
- Update triage duplicate regex to match configurable prefix
- Add Task Prefix input to dashboard SettingsModal UI
- Add tests for prefix-aware task allocation and settings modal

packages/core/src/store.test.ts

@@ -401,6 +401,42 @@ describe("TaskStore", () => {
     });
   });
 
+  // ── Task prefix tests ──────────────────────────────────────────
+
+  describe("taskPrefix setting", () => {
+    it("default prefix produces HAI-001 IDs", async () => {
+      const task = await store.createTask({ description: "Default prefix" });
+      expect(task.id).toBe("HAI-001");
+    });
+
+    it("custom prefix produces PROJ-001 IDs", async () => {
+      await store.updateSettings({ taskPrefix: "PROJ" });
+      const task = await store.createTask({ description: "Custom prefix" });
+      expect(task.id).toBe("PROJ-001");
+    });
+
+    it("prefix change mid-stream continues sequence", async () => {
+      const t1 = await store.createTask({ description: "First" });
+      const t2 = await store.createTask({ description: "Second" });
+      expect(t1.id).toBe("HAI-001");
+      expect(t2.id).toBe("HAI-002");
+
+      await store.updateSettings({ taskPrefix: "PROJ" });
+      const t3 = await store.createTask({ description: "Third" });
+      expect(t3.id).toBe("PROJ-003");
+    });
+
+    it("listTasks returns tasks regardless of prefix", async () => {
+      await store.createTask({ description: "HAI task" });
+      await store.updateSettings({ taskPrefix: "PROJ" });
+      await store.createTask({ description: "PROJ task" });
+
+      const tasks = await store.listTasks();
+      expect(tasks).toHaveLength(2);
+      expect(tasks.map((t) => t.id).sort()).toEqual(["HAI-001", "PROJ-002"]);
+    });
+  });
+
   describe("agent log persistence", () => {
     it("appendAgentLog creates agent.log and getAgentLogs reads it back", async () => {
       const task = await createTestTask();

packages/core/src/store.ts

@@ -160,7 +160,8 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
   private async allocateId(): Promise<string> {
     return this.withConfigLock(async () => {
       const config = await this.readConfig();
-      const id = `HAI-${String(config.nextId).padStart(3, "0")}`;
+      const prefix = config.settings?.taskPrefix || "HAI";
+      const id = `${prefix}-${String(config.nextId).padStart(3, "0")}`;
       config.nextId++;
       await this.writeConfig(config);
       return id;
@@ -235,7 +236,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
     const tasks: Task[] = [];
 
     for (const entry of entries) {
-      if (entry.isDirectory() && entry.name.startsWith("HAI-")) {
+      if (entry.isDirectory() && /^[A-Z]+-\d+$/.test(entry.name)) {
         try {
           tasks.push(await this.readTaskJson(join(this.tasksDir, entry.name)));
         } catch {
@@ -655,7 +656,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
     const taskId = normalizedParts[0];
     const file = normalizedParts[normalizedParts.length - 1];
     if (file !== "task.json") return;
-    if (!taskId.startsWith("HAI-")) return;
+    if (!/^[A-Z]+-\d+$/.test(taskId)) return;
 
     const fullPath = join(this.tasksDir, taskId, "task.json");
 

packages/core/src/types.ts

@@ -87,6 +87,10 @@ export interface Settings {
    *  of being deleted. New tasks acquire a warm worktree from the pool,
    *  preserving build caches (node_modules, target/, dist/). Default: false. */
   recycleWorktrees?: boolean;
+  /** Prefix for generated task IDs (e.g. `"HAI"` produces `HAI-001`).
+   *  Defaults to `"HAI"`. Only affects new tasks — existing tasks retain
+   *  their original IDs. */
+  taskPrefix?: string;
 }
 
 export const DEFAULT_SETTINGS: Settings = {
@@ -97,6 +101,7 @@ export const DEFAULT_SETTINGS: Settings = {
   autoMerge: false,
   worktreeInitCommand: undefined,
   recycleWorktrees: false,
+  taskPrefix: undefined,
 };
 
 export interface BoardConfig {