fix: resolve all CI mypy (265→0) and ruff (26→0) errors

- pyproject.toml: add mypy overrides for pandas/tabulate/matplotlib stubs,
  disable strict checking for vendored MyTT library
- config.py: use cast() for dict[str, Any] .get() returns
- beichi.py: widen _calc_bi_force param to BI | XD, import XD
- backtest/cli.py: split combo/single strategy into separate typed variables
- backtest/combo.py: add bool_array() helper for numpy return types
- chanlun/analyser.py: type ignore for pandas row access, fix dict type arg
- unified.py: change fields param from object to Any
- ex/mac_client.py: add type args to list literals
- cli/cmd_offline.py: wrap int market as Market enum before API call
- cli/cmd_chanlun.py: fix dict type arg
- offline/write_*.py: explicit int() cast for struct.unpack returns
- MyTT.py: fix line-too-long comments, UP038 isinstance syntax
- tests: fix E712 (==False → ~mask), E741 (noqa), F841, import sorting
- ruff format applied across codebase

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pyproject.toml

@@ -23,6 +23,15 @@ packages = ["src/easy_tdx"]
 strict = true
 python_version = "3.10"
 
+[[tool.mypy.overrides]]
+module = ["pandas", "tabulate", "matplotlib", "matplotlib.*"]
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "easy_tdx.MyTT"
+disallow_untyped_defs = false
+disallow_untyped_calls = false
+
 [tool.ruff]
 target-version = "py310"
 line-length = 100