fix: Gemini compressed prompt 키 불일치 및 해외 스캐너 GUBN=0 수정 (#242, #243)

- prompt_optimizer: build_compressed_prompt의 JSON 키를 act/conf/reason에서
  action/confidence/rationale로 수정 (parse_response와 일치시킴)
  → Gemini 응답 100% HOLD로 처리되던 버그 수정
- overseas: fetch_overseas_rankings의 GUBN 파라미터를 1(상승)에서 0(전체)으로 변경
  → 변동성 스캐너가 상승/하락 모두 대상으로 NASDAQ 후보 발견 가능
- test: GUBN==0 검증, build_compressed_prompt 키 이름 검증 추가

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/brain/prompt_optimizer.py

@@ -179,8 +179,8 @@ class PromptOptimizer:
             # Minimal instructions
             prompt = (
                 f"{market_name} trader. Analyze:\n{data_str}\n\n"
-                'Return JSON: {"act":"BUY"|"SELL"|"HOLD","conf":<0-100>,"reason":"<text>"}\n'
-                "Rules: act=BUY/SELL/HOLD, conf=0-100, reason=concise. No markdown."
+                'Return JSON: {"action":"BUY"|"SELL"|"HOLD","confidence":<0-100>,"rationale":"<text>"}\n'
+                "Rules: action=BUY/SELL/HOLD, confidence=0-100, rationale=concise. No markdown."
             )
         else:
             # Data only (for cached contexts where instructions are known)

src/broker/overseas.py

@@ -133,7 +133,7 @@ class OverseasBroker:
                 "AUTH": "",
                 "EXCD": ranking_excd,
                 "NDAY": "0",
-                "GUBN": "1",
+                "GUBN": "0",  # 0=전체(상승+하락), 1=상승만 — 변동성 스캐너는 전체 필요
                 "VOL_RANG": "0",
             }
 

tests/test_overseas_broker.py

@@ -124,7 +124,7 @@ class TestFetchOverseasRankings:
         assert "/uapi/overseas-stock/v1/ranking/updown-rate" in url
         assert params["EXCD"] == "NAS"
         assert params["NDAY"] == "0"
-        assert params["GUBN"] == "1"
+        assert params["GUBN"] == "0"  # 0=전체(상승+하락), 변동성 스캐너에 필요
         assert params["VOL_RANG"] == "0"
 
         overseas_broker._broker._auth_headers.assert_called_with("HHDFS76290000")

tests/test_token_efficiency.py

@@ -124,6 +124,10 @@ class TestPromptOptimizer:
         assert len(prompt) < 300
         assert "005930" in prompt
         assert "75000" in prompt
+        # Keys must match parse_response expectations (#242)
+        assert '"action"' in prompt
+        assert '"confidence"' in prompt
+        assert '"rationale"' in prompt
 
     def test_build_compressed_prompt_no_instructions(self):
         """Test compressed prompt without instructions."""