security: fix 5 review findings (2 high, 3 medium)

HIGH:
- Lock setup TOTP/NAS endpoints behind _require_setup() guard
  (prevented unauthenticated admin 2FA takeover after setup)
- Sanitize upload filename with Path().name + resolve() validation
  (prevented path traversal writing outside Inbox)

MEDIUM:
- Add score > 0.01 filter to hybrid search via subquery
  (prevented returning irrelevant documents with zero score)
- Implement Inbox → Knowledge file move after classification
  (classify_worker now moves files based on ai_domain)
- Add Anthropic Messages API support in _request()
  (premium/Claude path now sends correct format and parses
  content[0].text instead of choices[0].message.content)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/ai/client.py

@@ -89,19 +89,42 @@ class AIClient:
             raise
 
     async def _request(self, model_config, prompt: str) -> str:
-        """단일 모델 API 호출"""
-        response = await self._http.post(
-            model_config.endpoint,
-            json={
-                "model": model_config.model,
-                "messages": [{"role": "user", "content": prompt}],
-                "max_tokens": model_config.max_tokens,
-            },
-            timeout=model_config.timeout,
-        )
-        response.raise_for_status()
-        data = response.json()
-        return data["choices"][0]["message"]["content"]
+        """단일 모델 API 호출 (OpenAI 호환 + Anthropic Messages API)"""
+        is_anthropic = "anthropic.com" in model_config.endpoint
+
+        if is_anthropic:
+            import os
+            headers = {
+                "x-api-key": os.getenv("CLAUDE_API_KEY", ""),
+                "anthropic-version": "2023-06-01",
+                "content-type": "application/json",
+            }
+            response = await self._http.post(
+                model_config.endpoint,
+                headers=headers,
+                json={
+                    "model": model_config.model,
+                    "max_tokens": model_config.max_tokens,
+                    "messages": [{"role": "user", "content": prompt}],
+                },
+                timeout=model_config.timeout,
+            )
+            response.raise_for_status()
+            data = response.json()
+            return data["content"][0]["text"]
+        else:
+            response = await self._http.post(
+                model_config.endpoint,
+                json={
+                    "model": model_config.model,
+                    "messages": [{"role": "user", "content": prompt}],
+                    "max_tokens": model_config.max_tokens,
+                },
+                timeout=model_config.timeout,
+            )
+            response.raise_for_status()
+            data = response.json()
+            return data["choices"][0]["message"]["content"]
 
     async def close(self):
         await self._http.aclose()