feat(ai): 添加AI模块文档和重构前端AI组件

- 新增 docs/ai/README.md 包含完整的AI模块配置、建表、API文档
- 重构 src/views/ai/index.vue 组件，移除硬编码BASE_URL和多余参数
- 添加 src/api/ai/backend.ts 统一的AI后端API接口实现
- 集成模型列表、流式对话、非流式对话等功能
- 实现SE流式响应处理和鉴权头自动携带
- 移除历史消息存储和温度参数等冗余功能

src/api/ai/backend.ts

@@ -0,0 +1,200 @@
+import request from '@/utils/request';
+import type { ApiResult } from '@/api';
+import { API_BASE_URL, TOKEN_HEADER_NAME } from '@/config/setting';
+import { getToken } from '@/utils/token-util';
+import { getHostname, getTenantId } from '@/utils/domain';
+import { getMerchantId } from '@/utils/merchant';
+
+export interface AiModel {
+  name?: string;
+  id?: string;
+  [k: string]: unknown;
+}
+
+export interface AiChatRequest {
+  prompt: string;
+}
+
+function normalizeBaseURL(baseURL: string) {
+  return baseURL.replace(/\/+$/, '');
+}
+
+// Keep consistent with `src/utils/request.ts` but usable from `fetch` for SSE.
+function getRuntimeApiBaseURL(): string {
+  try {
+    const apiUrl = localStorage.getItem('ApiUrl');
+    if (apiUrl) return normalizeBaseURL(apiUrl);
+  } catch {
+    // ignore
+  }
+  return normalizeBaseURL(API_BASE_URL || '');
+}
+
+function buildAuthHeaders(): Record<string, string> {
+  const headers: Record<string, string> = {};
+  const token = getToken();
+  if (token) headers[TOKEN_HEADER_NAME] = token;
+
+  // Mirror axios interceptor behavior; add fallbacks to make localhost dev usable.
+  const tenantId =
+    getTenantId() ?? (localStorage.getItem('TenantId') || undefined);
+  if (tenantId) headers.TenantId = String(tenantId);
+
+  const companyId = localStorage.getItem('CompanyId');
+  if (companyId) headers.CompanyId = companyId;
+
+  const merchantId = getMerchantId?.();
+  if (merchantId) headers.MerchantId = String(merchantId);
+
+  const domain = getHostname?.();
+  if (domain) headers.Domain = domain;
+
+  return headers;
+}
+
+function extractText(payload: unknown): string {
+  if (payload == null) return '';
+  if (typeof payload === 'string') return payload;
+  if (typeof payload === 'number' || typeof payload === 'boolean') {
+    return String(payload);
+  }
+  if (Array.isArray(payload)) return payload.map(extractText).join('');
+  if (typeof payload === 'object') {
+    const obj: any = payload;
+    const candidates: unknown[] = [
+      obj.text,
+      obj.answer,
+      obj.content,
+      obj.data,
+      obj.message?.content,
+      obj.delta?.content,
+      obj.choices?.[0]?.delta?.content,
+      obj.choices?.[0]?.message?.content
+    ];
+    for (const c of candidates) {
+      const t = extractText(c);
+      if (t) return t;
+    }
+  }
+  return '';
+}
+
+export function normalizeModels(payload: unknown): AiModel[] {
+  if (!payload) return [];
+  if (Array.isArray(payload)) {
+    return payload.map((m) =>
+      typeof m === 'string' ? ({ name: m } as AiModel) : (m as AiModel)
+    );
+  }
+  if (typeof payload === 'object') {
+    const obj: any = payload;
+    if (Array.isArray(obj.models)) {
+      return obj.models.map((m: any) =>
+        typeof m === 'string' ? ({ name: m } as AiModel) : (m as AiModel)
+      );
+    }
+  }
+  return [];
+}
+
+/**
+ * 后端 AI 模块：GET /api/ai/models
+ * 前端 baseURL 一般已包含 `/api`，因此这里用相对路径 `/ai/models`。
+ */
+export async function aiListModels(): Promise<unknown> {
+  const res = await request.get<ApiResult<unknown>>('/ai/models');
+  if (res.data.code === 0) return res.data.data;
+  return Promise.reject(new Error(res.data.message));
+}
+
+/**
+ * 后端 AI 模块：POST /api/ai/chat
+ */
+export async function aiChat(body: AiChatRequest): Promise<string> {
+  const res = await request.post<ApiResult<unknown>>('/ai/chat', body);
+  if (res.data.code === 0) return extractText(res.data.data);
+  return Promise.reject(new Error(res.data.message));
+}
+
+/**
+ * 后端 AI 模块：POST /api/ai/chat/stream（SSE）
+ * 用 fetch 以便读取 ReadableStream，并附带鉴权/租户头。
+ */
+export async function aiChatStream(
+  body: AiChatRequest,
+  opts: {
+    signal?: AbortSignal;
+    onDelta: (text: string) => void;
+    onDone?: () => void;
+  }
+): Promise<void> {
+  const baseURL = getRuntimeApiBaseURL();
+  const url = `${baseURL}/ai/chat/stream`;
+
+  const res = await fetch(url, {
+    method: 'POST',
+    headers: {
+      Accept: 'text/event-stream',
+      'Content-Type': 'application/json',
+      ...buildAuthHeaders()
+    },
+    body: JSON.stringify(body),
+    signal: opts.signal
+  });
+
+  if (!res.ok || !res.body) {
+    const text = await res.text().catch(() => '');
+    throw new Error(
+      `aiChatStream failed: ${res.status} ${res.statusText}${
+        text ? ` - ${text}` : ''
+      }`
+    );
+  }
+
+  const reader = res.body.getReader();
+  const decoder = new TextDecoder('utf-8');
+  let buffer = '';
+
+  while (true) {
+    const { value, done } = await reader.read();
+    if (done) break;
+    buffer += decoder.decode(value, { stream: true });
+    // Some servers use CRLF; normalize to simplify parsing.
+    buffer = buffer.replace(/\r\n/g, '\n').replace(/\r/g, '\n');
+
+    // SSE events are separated by blank lines.
+    let idx = buffer.indexOf('\n\n');
+    while (idx !== -1) {
+      const rawEvent = buffer.slice(0, idx);
+      buffer = buffer.slice(idx + 2);
+      idx = buffer.indexOf('\n\n');
+
+      const dataParts: string[] = [];
+      for (const line of rawEvent.split('\n')) {
+        const trimmed = line.trimStart();
+        if (!trimmed.startsWith('data:')) continue;
+        dataParts.push(trimmed.slice(5).trimStart());
+      }
+      if (!dataParts.length) continue;
+
+      const data = dataParts.join('\n').trim();
+      if (!data) continue;
+      if (data === '[DONE]') {
+        opts.onDone?.();
+        return;
+      }
+
+      let delta = '';
+      try {
+        delta = extractText(JSON.parse(data));
+      } catch {
+        // Some servers stream plain text without JSON.
+        delta = data;
+      }
+
+      if (delta) opts.onDelta(delta);
+    }
+  }
+
+  opts.onDone?.();
+}