feat(dashboard): add React foundation and overview

apps/dashboard/src/api/client.ts

@@ -0,0 +1,60 @@
+import type { ZodType } from 'zod';
+import {
+  botStatsSchema,
+  controlResponseSchema,
+  timersSchema,
+  type BotStats,
+  type ControlResponse,
+  type Timers,
+} from './contracts.js';
+
+export class ApiError extends Error {
+  constructor(
+    message: string,
+    readonly status: number,
+  ) {
+    super(message);
+    this.name = 'ApiError';
+  }
+}
+
+interface ErrorPayload {
+  error?: unknown;
+}
+
+async function parseResponse<T>(response: Response, schema: ZodType<T>): Promise<T> {
+  const payload: unknown = await response.json();
+  if (!response.ok) {
+    const errorPayload = payload as ErrorPayload;
+    const message = typeof errorPayload.error === 'string' ? errorPayload.error : `Request failed (${response.status})`;
+    throw new ApiError(message, response.status);
+  }
+  return schema.parse(payload);
+}
+
+export interface DashboardApi {
+  getStats(): Promise<BotStats>;
+  getTimers(): Promise<Timers>;
+  setRunning(isRunning: boolean): Promise<ControlResponse>;
+}
+
+export function createDashboardApi(fetchImplementation?: typeof fetch): DashboardApi {
+  function request(input: RequestInfo | URL, init?: RequestInit): Promise<Response> {
+    return (fetchImplementation ?? globalThis.fetch)(input, init);
+  }
+
+  return {
+    async getStats() {
+      return parseResponse(await request('/api/stats'), botStatsSchema);
+    },
+    async getTimers() {
+      return parseResponse(await request('/api/timers'), timersSchema);
+    },
+    async setRunning(isRunning) {
+      const endpoint = isRunning ? '/api/start' : '/api/stop';
+      return parseResponse(await request(endpoint, { method: 'POST' }), controlResponseSchema);
+    },
+  };
+}
+
+export const dashboardApi = createDashboardApi();