chore: drop unused imports and a dead constant (no behaviour change)

- backtest/diagnose_filters: unused BacktestConfig import
- pair_signals/__init__: unused PlatformConfig import
- scripts/shadow_scan: unused pandas import
- research burst_precursors / calendar_impact / duka_spread: unused sys / COST / struct
- test_all: MagicMock, StringIO, Colors and two function-local imports that
  nothing in the test bodies used
- telegram_bot: ViolentWatch is only a type hint -> imported under TYPE_CHECKING

compare_oanda_tiingo.py and oanda_td_divergence.py are left alone here because
the hygiene commit deletes them.

Suite: 464 passed, 0 failed (unchanged).

Claude-Session: https://claude.ai/code/session_0156YhogLytzj9P2iH1skGbL

backtest/diagnose_filters.py

@@ -45,7 +45,6 @@ from gpu_backtest import (  # noqa: E402
     BAR_SECONDS,
     GPUTechnicalEngine,
     PAIR_ALIASES,
-    BacktestConfig,
     IndicatorCache,
     fetch_history,
     precompute_indicators,

backtest/research/burst_precursors.py

@@ -9,7 +9,7 @@ within/outside the scheduled-data hours, and an out-of-sample logistic model
 
     python backtest/research/burst_precursors.py PARQUET BAR_MINUTES [--k 3] [--start ... --end ...]
 """
-import argparse, sys
+import argparse
 import numpy as np, pandas as pd
 
 

backtest/research/calendar_impact.py

@@ -7,7 +7,7 @@ import argparse, sys
 from pathlib import Path
 import numpy as np, pandas as pd
 sys.path.insert(0, str(Path(__file__).resolve().parent))
-from open_trade_bursts import wilder_atr, simulate, r_of, stats, K, COST
+from open_trade_bursts import wilder_atr, simulate, r_of, stats, K
 
 CAL = Path(__file__).resolve().parent.parent / "cache" / "calendar.parquet"
 

backtest/research/duka_spread.py

@@ -10,7 +10,6 @@ bi5 format: LZMA 'alone' stream of 20-byte big-endian records
 XAUUSD prices scaled x1000. URL months are 0-indexed.
 """
 import lzma
-import struct
 import sys
 from concurrent.futures import ThreadPoolExecutor
 from datetime import date, timedelta

pair_signals/__init__.py

@@ -10,7 +10,7 @@ then register it in this file.
 
 from typing import Optional, List, Dict, Callable
 
-from config import PlatformConfig, Timeframe
+from config import Timeframe
 from signal_aggregator import SignalAggregator, SignalReport
 from providers import BaseDataProvider
 

scripts/shadow_scan.py

@@ -36,8 +36,6 @@ import time
 from datetime import datetime, timezone
 from pathlib import Path
 
-import pandas as pd
-
 sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
 
 from config import PlatformConfig, Timeframe, XAUUSD

telegram_bot.py

@@ -50,7 +50,7 @@ import threading
 import time
 from concurrent.futures import ThreadPoolExecutor
 from datetime import datetime, timezone
-from typing import Any, Dict, List, Optional, Set
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Set
 
 from telegram import InlineKeyboardButton, InlineKeyboardMarkup, Update
 from telegram.constants import ParseMode
@@ -77,7 +77,10 @@ from market_outlook import maybe_run_outlook
 from news_engine import FundamentalContext, NewsEngine
 from pair_signals import PAIR_PRODUCERS
 from signal_aggregator import SignalAggregator, SignalReport
-from violent_watch import ViolentWatch, attach_watch, should_send_headsup
+from violent_watch import attach_watch, should_send_headsup
+
+if TYPE_CHECKING:  # type hints only — ViolentWatch is never needed at runtime here
+    from violent_watch import ViolentWatch
 
 _APP = get_app_config()
 

test_all.py

@@ -12,8 +12,7 @@ import threading
 import tempfile
 import traceback
 from datetime import datetime, timedelta, timezone
-from unittest.mock import patch, MagicMock
-from io import StringIO
+from unittest.mock import patch
 
 import numpy as np
 import pandas as pd
@@ -1489,7 +1488,7 @@ print("\n═══ Module 6: main.py ═══")
 
 from main import (
     signal_color, quality_color, _compact_reason,
-    report_to_dict, build_config, Colors,
+    report_to_dict, build_config,
 )
 
 
@@ -2777,7 +2776,6 @@ def _():
 
 @test("CP: cp_patterns subset filter excludes disabled detectors")
 def _():
-    from dataclasses import replace
     df = make_cp_df(double_bottom_closes())
     cfg = XauStrategyConfig(cp_patterns=["bull_flag"])
     assert detect_chart_pattern(df, atr=5.0, cfg=cfg) is None
@@ -7757,7 +7755,6 @@ def _():
 @test("signal_log: analyze_pair weekend early-return is logged")
 def _():
     import signal_log as slog
-    from signal_aggregator import _is_forex_weekend
     fd, path = tempfile.mkstemp(suffix=".db")
     os.close(fd)
     os.remove(path)