feat: add professional financial data support via calc server

Add CALC_HOSTS, financial file list/record parsing (codec/financial.py),
new client methods (get_financial_file_list, get_financial_file,
get_financial_records) with async counterparts, and example 09 demo.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/unit/test_financial_data.py

@@ -0,0 +1,118 @@
+"""离线测试：专业财务数据解析。"""
+
+import struct
+
+from xmtdx.codec.financial import parse_financial_dat, parse_financial_file_list
+from xmtdx.models.finance import FinancialFileInfo, FinancialRecord
+
+
+class TestParseFinancialFileList:
+    def test_basic(self) -> None:
+        data = b"gpcw20260331.zip,abc123,5034901\ngpcw20251231.zip,def456,5737165\n"
+        result = parse_financial_file_list(data)
+        assert len(result) == 2
+        assert result[0] == ("gpcw20260331.zip", "abc123", 5034901)
+        assert result[1] == ("gpcw20251231.zip", "def456", 5737165)
+
+    def test_empty(self) -> None:
+        assert parse_financial_file_list(b"") == []
+
+    def test_blank_lines_skipped(self) -> None:
+        data = b"\ngpcw.zip,hash,100\n\n"
+        result = parse_financial_file_list(data)
+        assert len(result) == 1
+
+
+class TestParseFinancialDat:
+    def _build_dat(
+        self,
+        report_date: int = 20260331,
+        stocks: list[tuple[str, int, list[float]]] | None = None,
+    ) -> bytes:
+        """构造一个最小的 .dat 二进制文件。"""
+        if stocks is None:
+            stocks = [("600519", 1, [1.0, 2.0, 3.0])]
+
+        num_fields = len(stocks[0][2])
+        report_size = num_fields * 4
+        max_count = len(stocks)
+
+        # Header: <1h I 1H 3L = 20 bytes
+        header = struct.pack("<1hI1H3L", 0, report_date, max_count, 0, report_size, 0)
+
+        index_fmt = "<6s1c1L"
+        index_size = struct.calcsize(index_fmt)
+        header_size = struct.calcsize("<1hI1H3L")
+        data_start = header_size + max_count * index_size
+
+        report_fmt = f"<{num_fields}f"
+
+        # 先收集所有数据块，计算绝对偏移
+        data_chunks: list[bytes] = []
+        offset = data_start  # 绝对偏移
+        offsets: list[int] = []
+        for code, market_byte, fields in stocks:
+            offsets.append(offset)
+            chunk = struct.pack(report_fmt, *fields)
+            data_chunks.append(chunk)
+            offset += len(chunk)
+
+        # 组装 index
+        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]
+                )
+            )
+
+        return header + b"".join(index_entries) + b"".join(data_chunks)
+
+    def test_single_stock(self) -> None:
+        dat = self._build_dat(stocks=[("600519", 1, [1.5, 2.5, 3.5])])
+        result = parse_financial_dat(dat, report_date=20260331)
+        assert len(result) == 1
+        code, market, rdate, fields = result[0]
+        assert code == "600519"
+        assert market == b"\x01"  # SH
+        assert rdate == 20260331
+        assert len(fields) == 3
+        assert abs(fields[0] - 1.5) < 1e-6
+
+    def test_multiple_stocks(self) -> None:
+        stocks = [
+            ("000001", 0, [10.0, 20.0]),
+            ("600036", 1, [30.0, 40.0]),
+        ]
+        dat = self._build_dat(stocks=stocks)
+        result = parse_financial_dat(dat, report_date=20260630)
+        assert len(result) == 2
+        assert result[0][0] == "000001"
+        assert result[0][1] == b"\x00"  # SZ
+        assert result[1][0] == "600036"
+        assert result[1][1] == b"\x01"  # SH
+
+    def test_empty_data(self) -> None:
+        assert parse_financial_dat(b"") == []
+        assert parse_financial_dat(b"\x00" * 10) == []
+
+    def test_report_date_from_header(self) -> None:
+        dat = self._build_dat(report_date=20251231, stocks=[("000001", 0, [1.0])])
+        result = parse_financial_dat(dat)  # report_date=0, should use header
+        assert result[0][2] == 20251231
+
+
+class TestFinancialModels:
+    def test_file_info(self) -> None:
+        fi = FinancialFileInfo(filename="gpcw.zip", hash="abc", filesize=100)
+        assert fi.filename == "gpcw.zip"
+        assert fi.filesize == 100
+
+    def test_record(self) -> None:
+        from xmtdx.models.enums import Market
+
+        r = FinancialRecord(
+            code="600519", market=Market.SH, report_date=20260331, fields=[1.0, 2.0]
+        )
+        assert r.market == Market.SH
+        assert len(r.fields) == 2