Populate mime_type for assets in scanner and API paths

- Add custom MIME type registrations for model files (.safetensors, .pt, .ckpt, .gguf, .yaml)
- Pass mime_type through SeedAssetSpec to bulk_ingest
- Re-register types before use since server.py mimetypes.init() resets them
- Add tests for bulk ingest mime_type handling

Amp-Thread-ID: https://ampcode.com/threads/T-019c3626-c6ad-7139-a570-62da4e656a1a
Co-authored-by: Amp <amp@ampcode.com>

tests-unit/assets_test/services/test_bulk_ingest.py

@@ -0,0 +1,139 @@
+"""Tests for bulk ingest services."""
+
+from pathlib import Path
+
+import pytest
+from sqlalchemy.orm import Session
+
+from app.assets.database.models import Asset
+from app.assets.services.bulk_ingest import SeedAssetSpec, batch_insert_seed_assets
+
+
+class TestBatchInsertSeedAssets:
+    def test_populates_mime_type_for_model_files(self, session: Session, temp_dir: Path):
+        """Verify mime_type is stored in the Asset table for model files."""
+        file_path = temp_dir / "model.safetensors"
+        file_path.write_bytes(b"fake safetensors content")
+
+        specs: list[SeedAssetSpec] = [
+            {
+                "abs_path": str(file_path),
+                "size_bytes": 24,
+                "mtime_ns": 1234567890000000000,
+                "info_name": "Test Model",
+                "tags": ["models"],
+                "fname": "model.safetensors",
+                "metadata": None,
+                "hash": None,
+                "mime_type": "application/safetensors",
+            }
+        ]
+
+        result = batch_insert_seed_assets(session, specs=specs, owner_id="")
+
+        assert result.inserted_infos == 1
+
+        # Verify Asset has mime_type populated
+        assets = session.query(Asset).all()
+        assert len(assets) == 1
+        assert assets[0].mime_type == "application/safetensors"
+
+    def test_mime_type_none_when_not_provided(self, session: Session, temp_dir: Path):
+        """Verify mime_type is None when not provided in spec."""
+        file_path = temp_dir / "unknown.bin"
+        file_path.write_bytes(b"binary data")
+
+        specs: list[SeedAssetSpec] = [
+            {
+                "abs_path": str(file_path),
+                "size_bytes": 11,
+                "mtime_ns": 1234567890000000000,
+                "info_name": "Unknown File",
+                "tags": [],
+                "fname": "unknown.bin",
+                "metadata": None,
+                "hash": None,
+                "mime_type": None,
+            }
+        ]
+
+        result = batch_insert_seed_assets(session, specs=specs, owner_id="")
+
+        assert result.inserted_infos == 1
+
+        assets = session.query(Asset).all()
+        assert len(assets) == 1
+        assert assets[0].mime_type is None
+
+    def test_various_model_mime_types(self, session: Session, temp_dir: Path):
+        """Verify various model file types get correct mime_type."""
+        test_cases = [
+            ("model.safetensors", "application/safetensors"),
+            ("model.pt", "application/pytorch"),
+            ("model.ckpt", "application/pickle"),
+            ("model.gguf", "application/gguf"),
+        ]
+
+        specs: list[SeedAssetSpec] = []
+        for filename, mime_type in test_cases:
+            file_path = temp_dir / filename
+            file_path.write_bytes(b"content")
+            specs.append(
+                {
+                    "abs_path": str(file_path),
+                    "size_bytes": 7,
+                    "mtime_ns": 1234567890000000000,
+                    "info_name": filename,
+                    "tags": [],
+                    "fname": filename,
+                    "metadata": None,
+                    "hash": None,
+                    "mime_type": mime_type,
+                }
+            )
+
+        result = batch_insert_seed_assets(session, specs=specs, owner_id="")
+
+        assert result.inserted_infos == len(test_cases)
+
+        for filename, expected_mime in test_cases:
+            from app.assets.database.models import AssetInfo
+            info = session.query(AssetInfo).filter_by(name=filename).first()
+            assert info is not None
+            asset = session.query(Asset).filter_by(id=info.asset_id).first()
+            assert asset.mime_type == expected_mime, f"Expected {expected_mime} for {filename}, got {asset.mime_type}"
+
+
+class TestMetadataExtraction:
+    def test_extracts_mime_type_for_model_files(self, temp_dir: Path):
+        """Verify metadata extraction returns correct mime_type for model files."""
+        from app.assets.services.metadata_extract import extract_file_metadata
+
+        file_path = temp_dir / "model.safetensors"
+        file_path.write_bytes(b"fake safetensors content")
+
+        meta = extract_file_metadata(str(file_path))
+
+        assert meta.content_type == "application/safetensors"
+
+    def test_mime_type_for_various_model_formats(self, temp_dir: Path):
+        """Verify various model file types get correct mime_type from metadata."""
+        from app.assets.services.metadata_extract import extract_file_metadata
+
+        test_cases = [
+            ("model.safetensors", "application/safetensors"),
+            ("model.sft", "application/safetensors"),
+            ("model.pt", "application/pytorch"),
+            ("model.pth", "application/pytorch"),
+            ("model.ckpt", "application/pickle"),
+            ("model.pkl", "application/pickle"),
+            ("model.gguf", "application/gguf"),
+        ]
+
+        for filename, expected_mime in test_cases:
+            file_path = temp_dir / filename
+            file_path.write_bytes(b"content")
+
+            meta = extract_file_metadata(str(file_path))
+
+            assert meta.content_type == expected_mime, f"Expected {expected_mime} for {filename}, got {meta.content_type}"