refactor(assets): split queries.py into modular query modules

Split the ~1000 line app/assets/database/queries.py into focused modules:

- queries/asset.py - Asset entity queries (asset_exists_by_hash, get_asset_by_hash)
- queries/asset_info.py - AssetInfo queries (~15 functions)
- queries/cache_state.py - AssetCacheState queries (list_cache_states_by_asset_id,
  pick_best_live_path, prune_orphaned_assets, fast_db_consistency_pass)
- queries/tags.py - Tag queries (8 functions including ensure_tags_exist,
  add/remove tag functions, list_tags_with_usage)
- queries/__init__.py - Re-exports all public functions for backward compatibility

Also adds comprehensive unit tests using in-memory SQLite:
- tests-unit/assets_test/queries/conftest.py - Session fixture
- tests-unit/assets_test/queries/test_asset.py - 5 tests
- tests-unit/assets_test/queries/test_asset_info.py - 23 tests
- tests-unit/assets_test/queries/test_cache_state.py - 8 tests
- tests-unit/assets_test/queries/test_metadata.py - 12 tests for _apply_metadata_filter
- tests-unit/assets_test/queries/test_tags.py - 23 tests

All 71 unit tests pass. Existing integration tests unaffected.

Amp-Thread-ID: https://ampcode.com/threads/T-019c24bb-475b-7442-9ff9-8288edea3345
Co-authored-by: Amp <amp@ampcode.com>

tests-unit/assets_test/queries/test_metadata.py

@@ -0,0 +1,180 @@
+"""Tests for metadata filtering logic in asset_info queries."""
+import pytest
+from decimal import Decimal
+from sqlalchemy.orm import Session
+
+from app.assets.database.models import Asset, AssetInfo, AssetInfoMeta
+from app.assets.database.queries import list_asset_infos_page
+from app.assets.helpers import utcnow, project_kv
+
+
+def _make_asset(session: Session, hash_val: str) -> Asset:
+    asset = Asset(hash=hash_val, size_bytes=1024)
+    session.add(asset)
+    session.flush()
+    return asset
+
+
+def _make_asset_info(
+    session: Session,
+    asset: Asset,
+    name: str,
+    metadata: dict | None = None,
+) -> AssetInfo:
+    now = utcnow()
+    info = AssetInfo(
+        owner_id="",
+        name=name,
+        asset_id=asset.id,
+        user_metadata=metadata,
+        created_at=now,
+        updated_at=now,
+        last_access_time=now,
+    )
+    session.add(info)
+    session.flush()
+
+    if metadata:
+        for key, val in metadata.items():
+            for row in project_kv(key, val):
+                meta_row = AssetInfoMeta(
+                    asset_info_id=info.id,
+                    key=row["key"],
+                    ordinal=row.get("ordinal", 0),
+                    val_str=row.get("val_str"),
+                    val_num=row.get("val_num"),
+                    val_bool=row.get("val_bool"),
+                    val_json=row.get("val_json"),
+                )
+                session.add(meta_row)
+        session.flush()
+
+    return info
+
+
+class TestMetadataFilterString:
+    def test_filter_by_string_value(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "match", {"category": "models"})
+        _make_asset_info(session, asset, "nomatch", {"category": "images"})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"category": "models"})
+        assert total == 1
+        assert infos[0].name == "match"
+
+    def test_filter_by_string_no_match(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "item", {"category": "models"})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"category": "other"})
+        assert total == 0
+
+
+class TestMetadataFilterNumeric:
+    def test_filter_by_int_value(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "epoch5", {"epoch": 5})
+        _make_asset_info(session, asset, "epoch10", {"epoch": 10})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"epoch": 5})
+        assert total == 1
+        assert infos[0].name == "epoch5"
+
+    def test_filter_by_float_value(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "high", {"score": 0.95})
+        _make_asset_info(session, asset, "low", {"score": 0.5})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"score": 0.95})
+        assert total == 1
+        assert infos[0].name == "high"
+
+
+class TestMetadataFilterBoolean:
+    def test_filter_by_true(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "active", {"enabled": True})
+        _make_asset_info(session, asset, "inactive", {"enabled": False})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"enabled": True})
+        assert total == 1
+        assert infos[0].name == "active"
+
+    def test_filter_by_false(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "active", {"enabled": True})
+        _make_asset_info(session, asset, "inactive", {"enabled": False})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"enabled": False})
+        assert total == 1
+        assert infos[0].name == "inactive"
+
+
+class TestMetadataFilterNull:
+    def test_filter_by_null_matches_missing_key(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "has_key", {"optional": "value"})
+        _make_asset_info(session, asset, "missing_key", {})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"optional": None})
+        assert total == 1
+        assert infos[0].name == "missing_key"
+
+    def test_filter_by_null_matches_explicit_null(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "explicit_null", {"nullable": None})
+        _make_asset_info(session, asset, "has_value", {"nullable": "present"})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"nullable": None})
+        assert total == 1
+        assert infos[0].name == "explicit_null"
+
+
+class TestMetadataFilterList:
+    def test_filter_by_list_or(self, session: Session):
+        """List values should match ANY of the values (OR)."""
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "cat_a", {"category": "a"})
+        _make_asset_info(session, asset, "cat_b", {"category": "b"})
+        _make_asset_info(session, asset, "cat_c", {"category": "c"})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={"category": ["a", "b"]})
+        assert total == 2
+        names = {i.name for i in infos}
+        assert names == {"cat_a", "cat_b"}
+
+
+class TestMetadataFilterMultipleKeys:
+    def test_multiple_keys_and(self, session: Session):
+        """Multiple keys should ALL match (AND)."""
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "match", {"type": "model", "version": 2})
+        _make_asset_info(session, asset, "wrong_type", {"type": "config", "version": 2})
+        _make_asset_info(session, asset, "wrong_version", {"type": "model", "version": 1})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(
+            session, metadata_filter={"type": "model", "version": 2}
+        )
+        assert total == 1
+        assert infos[0].name == "match"
+
+
+class TestMetadataFilterEmptyDict:
+    def test_empty_filter_returns_all(self, session: Session):
+        asset = _make_asset(session, "hash1")
+        _make_asset_info(session, asset, "a", {"key": "val"})
+        _make_asset_info(session, asset, "b", {})
+        session.commit()
+
+        infos, _, total = list_asset_infos_page(session, metadata_filter={})
+        assert total == 2