fix: add unified ledger amount and enforce manual decimal precision

Co-authored-by: genichin <4282227+genichin@users.noreply.github.com>

tests/test_v1_portfolios_manual_ledger.py

@@ -500,6 +500,30 @@ def test_dividend_requires_executed_at_and_rejects_fee_field() -> None:
     assert invalid_fee.status_code == 422
 
 
+def test_dividend_rejects_sub_minimum_numeric_precision() -> None:
+    repo = _FakeRepo(_portfolio())
+    client = _make_client(repo)
+
+    too_precise = client.post(
+        f"/v1/portfolios/{_PORTFOLIO_ID}/ledger/manual",
+        json={"action": "DIVIDEND", "amount": "0.000000004", "executed_at": "2026-09-01"},
+        headers=_auth(),
+    )
+    assert too_precise.status_code == 422
+
+
+def test_dividend_rejects_amount_exceeding_numeric_20_8() -> None:
+    repo = _FakeRepo(_portfolio())
+    client = _make_client(repo)
+
+    too_large = client.post(
+        f"/v1/portfolios/{_PORTFOLIO_ID}/ledger/manual",
+        json={"action": "DIVIDEND", "amount": "1000000000000.00000000", "executed_at": "2026-09-01"},
+        headers=_auth(),
+    )
+    assert too_large.status_code == 422
+
+
 def test_dividend_duplicate_requires_confirmation() -> None:
     repo = _FakeRepo(_portfolio())
     client = _make_client(repo)
@@ -571,12 +595,24 @@ def test_unified_ledger_includes_dividend_fields() -> None:
     item = resp.json()["items"][0]
     assert item["source"] == "manual"
     assert item["action"] == "DIVIDEND"
+    assert item["amount"] == 33.0
+    assert item["price"] == 33.0
     assert item["executed_at"] == "2026-09-01T00:00:00Z"
     assert item["tax_amount"] == 3.0
     assert item["note"] == "Q3"
     assert item["profit_buffer_after"] == created.json()["profit_buffer_after"]
 
 
+def test_unified_ledger_openapi_contains_nullable_amount() -> None:
+    repo = _FakeRepo(_portfolio())
+    client = _make_client(repo)
+
+    response = client.get("/openapi.json")
+    assert response.status_code == 200
+    schemas = response.json()["components"]["schemas"]
+    assert "amount" in schemas["LedgerHistoryItem"]["properties"]
+
+
 def test_reversal_rejects_fee_tax_and_missing_target() -> None:
     repo = _FakeRepo(_portfolio())
     client = _make_client(repo)