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/ai.py

@@ -0,0 +1,149 @@
+"""AI 模型配置：每个组织可在页面配置 OpenAI 或本地 OpenAI 兼容服务（Ollama / LM Studio / vLLM 等）。
+
+数据库配置优先；未配置时回退到环境变量（AI_ENABLED / OPENAI_*），保持旧行为兼容。
+API Key 只存后端，读取接口只做脱敏回显，绝不把密钥下发到浏览器。
+"""
+
+import httpx
+from django.conf import settings
+from django.http import JsonResponse
+
+from .models import AIConfig
+from .views import APIError, audit, body, endpoint
+
+PROVIDERS = ("openai", "local")
+OPENAI_BASE_URL = "https://api.openai.com/v1"
+
+
+def require_full_admin(request):
+    if request.member.departments:
+        raise APIError("没有配置 AI 模型的权限", 403)
+
+
+def resolve(org):
+    """返回生效的 AI 配置字典；未启用或配置不完整时返回 None。"""
+    cfg = AIConfig.objects.filter(organization=org).first()
+    if cfg:
+        base_url = (cfg.base_url or "").rstrip("/") or (OPENAI_BASE_URL if cfg.provider == "openai" else "")
+        key_required = cfg.provider == "openai"
+        if not cfg.enabled or not base_url or not cfg.model or (key_required and not cfg.api_key):
+            return None
+        return {
+            "enabled": True,
+            "provider": cfg.provider,
+            "base_url": base_url,
+            "api_key": cfg.api_key,
+            "model": cfg.model,
+        }
+    if settings.AI_ENABLED and settings.OPENAI_API_KEY and settings.OPENAI_MODEL:
+        return {
+            "enabled": True,
+            "provider": "openai",
+            "base_url": (settings.OPENAI_BASE_URL or OPENAI_BASE_URL).rstrip("/"),
+            "api_key": settings.OPENAI_API_KEY,
+            "model": settings.OPENAI_MODEL,
+        }
+    return None
+
+
+def org_models_endpoint(org):
+    """组织配置或环境回退的 base_url/api_key，用于探测模型列表。"""
+    cfg = AIConfig.objects.filter(organization=org).first()
+    if cfg:
+        base_url = (cfg.base_url or "").rstrip("/") or (OPENAI_BASE_URL if cfg.provider == "openai" else "")
+        return base_url, cfg.api_key
+    return (settings.OPENAI_BASE_URL or OPENAI_BASE_URL).rstrip("/"), settings.OPENAI_API_KEY
+
+
+@endpoint(("GET", "PUT"), roles=("admin",))
+def ai_config(request):
+    require_full_admin(request)
+    org = request.member.organization
+    if request.method == "GET":
+        cfg = AIConfig.objects.filter(organization=org).first()
+        return JsonResponse(
+            {
+                "enabled": cfg.enabled if cfg else False,
+                "provider": cfg.provider if cfg else "local",
+                "base_url": cfg.base_url if cfg else "",
+                "model": cfg.model if cfg else "",
+                "api_key_set": bool(cfg and cfg.api_key),
+                "updated_at": cfg.updated_at.isoformat() if cfg else None,
+            }
+        )
+    data = body(request)
+    enabled = data.get("enabled")
+    provider = data.get("provider")
+    base_url = data.get("base_url", "")
+    api_key = data.get("api_key", "")
+    model = data.get("model", "")
+    if type(enabled) is not bool or provider not in PROVIDERS:
+        raise APIError("AI 配置参数无效")
+    if not isinstance(base_url, str) or len(base_url) > 500:
+        raise APIError("Base URL 无效")
+    base_url = base_url.rstrip("/")
+    if base_url and not base_url.startswith(("http://", "https://")):
+        raise APIError("Base URL 必须以 http:// 或 https:// 开头")
+    if not isinstance(api_key, str) or len(api_key) > 500:
+        raise APIError("API Key 无效")
+    if not isinstance(model, str) or len(model) > 200:
+        raise APIError("模型名无效")
+    cfg = AIConfig.objects.filter(organization=org).first()
+    if enabled:
+        if provider == "local" and not base_url:
+            raise APIError("本地服务需要填写 Base URL，例如 http://127.0.0.1:11434/v1")
+        if provider == "openai" and not (api_key or (cfg and cfg.api_key)):
+            raise APIError("OpenAI 服务需要 API Key")
+        if not model:
+            raise APIError("启用前需要填写模型名，可点击“获取可用模型”选择")
+    key_changed = bool(api_key)
+    defaults = {
+        "enabled": enabled,
+        "provider": provider,
+        "base_url": base_url,
+        "model": model,
+    }
+    if api_key:
+        defaults["api_key"] = api_key
+    if not cfg:
+        AIConfig.objects.create(organization=org, **defaults)
+    else:
+        for field, value in defaults.items():
+            setattr(cfg, field, value)
+        cfg.save()
+    audit(
+        request,
+        "ai_config.update",
+        details={
+            "provider": provider,
+            "model": model,
+            "enabled": enabled,
+            "key_changed": key_changed,
+        },
+    )
+    return JsonResponse({"ok": True})
+
+
+@endpoint(roles=("admin",))
+def ai_models(request):
+    require_full_admin(request)
+    base_url, api_key = org_models_endpoint(request.member.organization)
+    if not base_url:
+        raise APIError("请先保存 Base URL 再获取模型列表", 400)
+    headers = {"Authorization": f"Bearer {api_key}"} if api_key else {}
+    try:
+        with httpx.Client(timeout=10) as client:
+            response = client.get(f"{base_url}/models", headers=headers)
+            response.raise_for_status()
+            data = response.json()
+        items = data.get("data", [])
+        ids = [m.get("id") for m in items if isinstance(m, dict) and isinstance(m.get("id"), str)]
+        if not ids and isinstance(data.get("models"), list):
+            ids = [
+                m.get("name")
+                for m in data["models"]
+                if isinstance(m, dict) and isinstance(m.get("name"), str)
+            ]
+        return JsonResponse({"items": ids[:200]})
+    except (httpx.HTTPError, ValueError, AttributeError) as exc:
+        raise APIError("无法从该服务获取模型列表，请检查 Base URL 与 API Key", 502) from exc