feat(ai): 页面可配置云端或本地 OpenAI 兼容模型

- 新增 AIConfig 模型（每组织一份，迁移 0005）与 /api/ai-config、
  /api/ai-models 接口；密钥只存后端、读取脱敏、修改记审计
- 支持 OpenAI 及本地 OpenAI 兼容服务（Ollama/LM Studio/vLLM），
  可从 /v1/models 一键获取模型列表多选一；数据库配置优先于环境变量
- 助手调用走生效配置，Copilot 文案同步更新
- 全权限管理员可在「管理 → AI 模型」配置；补接口级测试

finance/assistant.py

@@ -1,14 +1,17 @@
 import json
 
 import httpx
-from django.conf import settings
 from django.http import JsonResponse
 
+from .ai import resolve
 from .analysis import METRICS, analyze, context, dimensions
 from .views import APIError, audit, body, dataset, endpoint, limit, preferences
 
 
-def model_intent(question, ds, ctx):
+def model_intent(question, ds, ctx, cfg=None):
+    cfg = cfg or resolve(ds.organization)
+    if not cfg:
+        raise APIError("尚未配置外部 AI 服务", 503)
     keys = [d["key"] for d in dimensions(ds)]
     schema = {
         "type": "object",
@@ -31,7 +34,7 @@ def model_intent(question, ds, ctx):
     }
     # Only schema, selected context and the user's question leave the server; never raw rows.
     payload = {
-        "model": settings.OPENAI_MODEL,
+        "model": cfg["model"],
         "store": False,
         "max_output_tokens": 1200,
         "input": [
@@ -55,8 +58,8 @@ def model_intent(question, ds, ctx):
     try:
         with httpx.Client(timeout=30) as client:
             response = client.post(
-                "https://api.openai.com/v1/responses",
-                headers={"Authorization": f"Bearer {settings.OPENAI_API_KEY}"},
+                f"{cfg['base_url']}/responses",
+                headers={"Authorization": f"Bearer {cfg['api_key']}"} if cfg["api_key"] else {},
                 json=payload,
             )
             response.raise_for_status()
@@ -107,12 +110,15 @@ def assistant(request, dataset_id):
     use_model = data.get("use_model", False)
     if type(use_model) is not bool:
         raise APIError("AI 模式必须为布尔值")
+    provider = "local"
     if use_model:
-        if not (settings.AI_ENABLED and settings.OPENAI_API_KEY and settings.OPENAI_MODEL):
-            raise APIError("尚未配置外部 AI 服务", 503)
+        cfg = resolve(request.member.organization)
+        if not cfg:
+            raise APIError("尚未配置外部 AI 服务；请管理员在「AI 模型」中配置", 503)
         if data.get("consent") is not True:
             raise APIError("请先同意发送问题与当前筛选上下文", 400)
-        intent = model_intent(question, ds, ctx)
+        provider = cfg["provider"]
+        intent = model_intent(question, ds, ctx, cfg)
     else:
         action = (
             "evidence"
@@ -140,21 +146,19 @@ def assistant(request, dataset_id):
     else:
         change = value["change"]
         change_text = f"{change:+.1%}" if change is not None else "不可计算（基期为零或数据缺失）"
-        answer = f"当前范围{METRICS[metric]}为 {value['current']:,.4f}，较基期变化 {change_text}。按当前规则识别出 {result['anomaly_count']} 个异常分组。"
+        answer = f"当前范围{METRICS[metric]}为 {value['current']:,.2f}，较基期变化 {change_text}。按当前规则识别出 {result['anomaly_count']} 个异常分组。"
         candidates = [r for r in result["rows"] if r["anomaly"]][:3]
         if candidates:
             answer += " 优先核查：" + "、".join(r["label"] for r in candidates) + "。"
         answer += " 这是数据贡献分解，不是因果结论。"
-    audit(
-        request, "assistant.query", ds.pk, {"provider": "openai" if use_model else "local", "intent": intent}
-    )
+    audit(request, "assistant.query", ds.pk, {"provider": provider, "intent": intent})
     return JsonResponse(
         {
             "answer": answer,
             "intent": intent,
             "context": result["context"],
             "version": ds.sha256,
-            "provider": "openai" if use_model else "local",
+            "provider": provider,
             "evidence": [
                 {"label": r["label"], "filters": r["filters"], "values": r["values"][metric]}
                 for r in result["rows"][:5]