fix(ledger): disjoint unified action schema and refresh req-001 traceability docs

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

tests/test_v1_portfolios_manual_ledger.py

@@ -12,10 +12,12 @@ from unittest.mock import patch
 
 import pytest
 from fastapi.testclient import TestClient
+from pydantic import ValidationError
 
 from app.core.config import Settings, get_settings
 from app.domain.models import LedgerEntry, Portfolio, TokenPrincipal
 from app.main import create_app
+from app.schemas.v1 import LedgerHistoryItem
 
 _PORTFOLIO_ID = "pf-001"
 _USER_ID = "user-001"
@@ -987,6 +989,21 @@ def test_unified_ledger_openapi_contains_nullable_amount() -> None:
     history_amount_types = {option.get("type") for option in schemas["LedgerHistoryItem"]["properties"]["amount"]["anyOf"]}
     assert history_amount_types == {"number", "null"}
     assert schemas["DividendLedgerHistoryItem"]["properties"]["amount"]["type"] == "string"
+    assert "DIVIDEND" not in schemas["LedgerHistoryItem"]["properties"]["action"]["enum"]
+    assert schemas["DividendLedgerHistoryItem"]["properties"]["action"]["const"] == "DIVIDEND"
+
+
+def test_unified_ledger_history_item_rejects_dividend_numeric_branch_payload() -> None:
+    with pytest.raises(ValidationError):
+        LedgerHistoryItem(
+            ledger_entry_id=1,
+            portfolio_id=_PORTFOLIO_ID,
+            source="manual",
+            action="DIVIDEND",
+            recorded_at=datetime.now(UTC),
+            amount=1.0,
+            tax_amount=0.0,
+        )
 
 
 def test_reversal_rejects_fee_tax_and_missing_target() -> None: