feat(tinvest): источник T-Invest — операции, снапшоты и справочник

SDK t_tech.invest импортируется ровно в client.py: остальной код видит обычные
Decimal и dataclass'ы. Операции читаются по курсору GetOperationsByCursor,
снапшоты GetPortfolio/GetPositions складываются в position_snapshot и
cash_snapshot — только для сверки, аналитика их не читает.

mapper.py — явный словарь OperationType -> EventKind на все значения enum SDK,
покрытый тестом: новый тип должен ломать тест, а не молча уезжать в other.

Покупка с привязанной карты помечается meta.card_funded: деньги пришли снаружи,
баланс счёта их не видел, и для доходности это внешний поток, а не внутреннее
движение.

backend/tests/sources/test_tinvest_client.py

@@ -0,0 +1,128 @@
+"""Flattening of SDK records — the places where real data bit us.
+
+These use light stand-ins rather than SDK objects: the point is the flattening rules, and
+the suite must stay runnable without a token or a network.
+"""
+
+import enum
+from dataclasses import dataclass
+from datetime import UTC, datetime
+from decimal import Decimal
+from typing import Any, cast
+
+from fintracker.sources.tinvest.client import _as_dict, _kind_of, _money, _operation
+
+
+@dataclass
+class Money:
+    currency: str
+    units: int
+    nano: int
+
+
+class Kind(enum.Enum):
+    """Stands in for the SDK's OperationType, which is a real Enum."""
+
+    OPERATION_TYPE_BUY = 15
+
+
+@dataclass
+class Item:
+    """Only the fields `_operation` reads."""
+
+    id: str
+    type: Kind
+    date: datetime
+    instrument_uid: str
+    position_uid: str
+    figi: str
+    payment: Money
+    price: Money
+    commission: Money
+    accrued_int: Money
+    description: str
+    quantity: int
+    quantity_done: int
+
+
+def item(**over) -> Item:
+    base = {
+        "id": "42",
+        "type": Kind.OPERATION_TYPE_BUY,
+        "date": datetime(2026, 4, 16, 18, 11, tzinfo=UTC),
+        "instrument_uid": "uid-1",
+        "position_uid": "pos-1",
+        "figi": "TCS00A10B7T7",
+        "payment": Money("rub", -984, -780000000),
+        "price": Money("rub", 984, 780000000),
+        "commission": Money("rub", -2, -940000000),
+        "accrued_int": Money("", 0, 0),
+        "description": "Покупка 1 облигации",
+        "quantity": 12,
+        "quantity_done": 1,
+    }
+    return Item(**{**base, **over})
+
+
+def test_money_is_exact_not_float():
+    """units+nano must land as an exact Decimal — money never goes through float."""
+    assert _money(Money("rub", -984, -780000000)) == Decimal("-984.78")
+    assert _money(Money("rub", 0, 500000000)) == Decimal("0.5")
+
+
+def op_of(**over):
+    """`_operation` on the stand-in; the cast is for pyright, the fields are what matter."""
+    return _operation("acc", cast("Any", item(**over)))
+
+
+def test_quantity_uses_what_executed_not_what_was_ordered():
+    """A partially filled order reports quantity=12, quantity_done=1 — the position grew by 1."""
+    assert op_of().quantity == Decimal(1)
+
+
+def test_quantity_falls_back_when_done_is_absent():
+    assert op_of(quantity_done=0, quantity=7).quantity == Decimal(7)
+
+
+def test_operation_keeps_position_uid():
+    """The identity that survives T-Invest handing one paper several instrument uids."""
+    assert op_of().position_uid == "pos-1"
+
+
+def test_payload_is_queryable_json_not_a_repr_string():
+    """The raw tier exists to be re-derived from; `repr()` prose would defeat that."""
+    payload = op_of().payload
+    assert payload["id"] == "42"
+    assert payload["type"] == "OPERATION_TYPE_BUY"
+    assert payload["quantity_done"] == 1
+    # MoneyValue collapses to an exact decimal string plus its currency
+    assert payload["payment"] == {"value": "-984.78", "currency": "rub"}
+    assert payload["date"] == "2026-04-16T18:11:00+00:00"
+
+
+def test_as_dict_expands_the_top_level_record_by_field():
+    """The record itself becomes a dict of its fields; money nested inside it collapses."""
+    assert _as_dict(Money("rub", 1, 500000000)) == {
+        "currency": "rub",
+        "units": 1,
+        "nano": 500000000,
+    }
+
+
+def test_kind_prefers_what_the_api_states():
+    """Guessing from the record's shape filed the rouble position as a share."""
+
+    @dataclass
+    class Rouble:
+        instrument_type: str
+        maturity_date: None = None
+
+    assert _kind_of(Rouble("currency")) == "currency"
+
+
+def test_kind_falls_back_to_shape_when_unstated():
+    @dataclass
+    class Bond:
+        maturity_date: datetime
+
+    assert _kind_of(Bond(datetime(2030, 1, 1, tzinfo=UTC))) == "bond"