feat(signal_v2-phase3a): config + state extensions for KIS data

- config.py: KIS_APP_KEY/SECRET/ACCOUNT/IS_VIRTUAL + V1_TOKEN_PATH env
- state.py: PollState extended with minute_bars (deque) and asking_price
- requirements.txt: websockets>=12

19 existing tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

requirements.txt

@@ -6,3 +6,4 @@ python-dotenv>=1.0
 pytest>=8.0
 pytest-asyncio>=0.23
 respx>=0.21
+websockets>=12