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>

tests/unit/test_financial_data.py

@@ -61,9 +61,7 @@ class TestParseFinancialDat:
         index_entries: list[bytes] = []
         for i, (code, market_byte, _) in enumerate(stocks):
             index_entries.append(
-                struct.pack(
-                    index_fmt, code.encode("ascii"), bytes([market_byte]), offsets[i]
-                )
+                struct.pack(index_fmt, code.encode("ascii"), bytes([market_byte]), offsets[i])
             )
 
         return header + b"".join(index_entries) + b"".join(data_chunks)