fix: add unified ledger amount and enforce manual decimal precision

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

tests/test_bat025_portfolio_ledger_manual_metadata_migration.py

@@ -10,6 +10,7 @@ from __future__ import annotations
 
 import os
 from datetime import datetime, timezone
+from decimal import Decimal
 from urllib.parse import unquote, urlparse
 from uuid import uuid4
 
@@ -271,3 +272,43 @@ def test_broker_and_manual_ledger_writes_regress_after_real_upgrade(
         )
         assert cur.fetchone() == ("manual", "bat025-user", "synthetic-local-fixture")
     repo.close()
+
+
+def test_dividend_precision_and_reversal_round_trip_on_real_postgres(
+    isolated_settings: Settings,
+) -> None:
+    """DIVIDEND min unit persists and REVERSAL removes the same amount exactly."""
+    upgrade_to_head(isolated_settings)
+    repo = _repo(isolated_settings)
+    portfolio_id = _seed_portfolio(repo, "dividend-precision")
+
+    dividend = repo.record_manual_ledger(
+        portfolio_id,
+        action="DIVIDEND",
+        amount=Decimal("0.00000001"),
+        tax=Decimal("0.00000001"),
+        executed_at=datetime(2026, 9, 1, 0, 0, 0, tzinfo=timezone.utc),
+        note="precision-test",
+    )
+
+    assert dividend.price == 0.00000001
+    assert dividend.tax_amount == 0.00000001
+    assert dividend.profit_buffer_after == 0.00000001
+    with repo._connect().cursor() as cur:
+        cur.execute(
+            "SELECT price::text, tax_amount::text, profit_buffer_after::text FROM portfolio_ledger WHERE ledger_entry_id = %s",
+            (dividend.ledger_entry_id,),
+        )
+        assert cur.fetchone() == ("0.00000001", "0.00000001", "0.00000001")
+
+    reversal = repo.record_manual_ledger(
+        portfolio_id,
+        action="REVERSAL",
+        target_ledger_entry_id=dividend.ledger_entry_id,
+    )
+    assert reversal.profit_buffer_after == 0.0
+    with repo._connect().cursor() as cur:
+        cur.execute("SELECT profit_buffer::text FROM portfolios WHERE portfolio_id = %s", (portfolio_id,))
+        assert cur.fetchone()[0] == "0"
+
+    repo.close()

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)