feat(REQ-006): implement v1 assets endpoint with verification

- Add v1_assets.py API endpoint for asset list retrieval
- Add AssetResponse schema to v1.py
- Implement comprehensive test coverage in test_v1.py
- Update requirement verification with implementation evidence
- Update SRS index to mark REQ-006 as Implemented
- Document acceptance criteria validation results

tests/test_v1.py

@@ -177,6 +177,7 @@ def test_v1_assets_returns_asset_list(monkeypatch) -> None:
     assert item["cash"] == 1000.0
     assert item["quantity"] == 10.0
     assert item["strategy_params"] == {}
+    assert item["strategy_type"] is None
 
 
 def test_v1_assets_status_filter(monkeypatch) -> None:
@@ -239,6 +240,7 @@ def test_v1_assets_strategy_params(monkeypatch) -> None:
 
     assert resp.status_code == 200
     assert resp.json()["assets"][0]["strategy_params"] == {"buy_threshold": 0.05}
+    assert resp.json()["assets"][0]["strategy_type"] == "strategy"
 
 
 def test_v1_assets_strategy_params_fallback_on_error(monkeypatch) -> None:
@@ -267,6 +269,7 @@ def test_v1_assets_strategy_params_fallback_on_error(monkeypatch) -> None:
 
     assert resp.status_code == 200
     assert resp.json()["assets"][0]["strategy_params"] == {}
+    assert resp.json()["assets"][0]["strategy_type"] is None
 
 
 # ---------------------------------------------------------------------------