feat(settings): filename templates for download and bulk rename (#1071)

Add per-model-type filename templates ({model_name}, {version_name},
{base_model}, {author}, {first_tag}, {hash_short}, {original_name}) so
downloaded files get informative names instead of e.g. V1.safetensors.
Empty template keeps the current filename (opt-in, off by default).

- apply template automatically after downloads; rename conflicts keep
  the original name and never fail the download
- record original_file_name in metadata on rename for traceability
- bulk apply via GET|POST /api/lm/{prefix}/apply-filename-template with
  WebSocket progress, sharing the auto-organize lock
- settings UI lives in the new Organization tab with validation, live
  preview, and per-type 'apply to library' actions

tests/services/test_download_filename_template.py

@@ -0,0 +1,147 @@
+"""Tests for the post-download filename template rename phase."""
+
+import json
+from pathlib import Path
+
+import pytest
+
+from py.services.download_manager import DownloadManager
+from py.services.service_registry import ServiceRegistry
+from py.services.settings_manager import get_settings_manager
+
+
+class DummyScanner:
+    def __init__(self, root: Path):
+        self._root = root
+        self.model_type = "lora"
+        self.updates = []
+
+    def get_model_roots(self):
+        return [str(self._root)]
+
+    async def update_single_model_cache(self, original_path, new_path, metadata):
+        self.updates.append((original_path, new_path, metadata))
+        return True
+
+
+@pytest.fixture
+def download_manager() -> DownloadManager:
+    return DownloadManager()
+
+
+@pytest.fixture(autouse=True)
+def no_recipe_scanner(monkeypatch: pytest.MonkeyPatch):
+    async def _no_scanner():
+        return None
+
+    monkeypatch.setattr(ServiceRegistry, "get_recipe_scanner", _no_scanner)
+
+
+def _set_template(template: str, model_type: str = "lora") -> None:
+    manager = get_settings_manager()
+    templates = dict(manager.settings.get("download_filename_templates") or {})
+    templates[model_type] = template
+    manager.settings["download_filename_templates"] = templates
+
+
+def _write_model(root: Path, stem: str, model_name: str, sha256: str) -> Path:
+    model_path = root / f"{stem}.safetensors"
+    model_path.write_bytes(b"model")
+    metadata_path = root / f"{stem}.metadata.json"
+    metadata_path.write_text(
+        json.dumps(
+            {
+                "file_name": stem,
+                "file_path": model_path.as_posix(),
+                "model_name": model_name,
+                "sha256": sha256,
+                "civitai": {"id": 1},
+            }
+        )
+    )
+    return model_path
+
+
+async def test_download_rename_applies_filename_template(
+    tmp_path: Path, download_manager: DownloadManager
+):
+    _set_template("{model_name}-{hash_short}")
+    model_path = _write_model(tmp_path, "V1", "My Model", "abcdef0123456789")
+    download_manager._active_downloads["dl1"] = {"file_path": model_path.as_posix()}
+
+    downloaded_metadata = [
+        {
+            "file_path": model_path.as_posix(),
+            "file_name": "V1",
+            "model_name": "My Model",
+            "sha256": "abcdef0123456789",
+            "civitai": {"id": 1},
+        }
+    ]
+
+    await download_manager._apply_download_filename_template(
+        scanner=DummyScanner(tmp_path),
+        model_type="lora",
+        downloaded_metadata=downloaded_metadata,
+        download_id="dl1",
+    )
+
+    new_path = tmp_path / "My Model-abcdef0123.safetensors"
+    assert new_path.exists()
+    assert not model_path.exists()
+
+    new_metadata = json.loads(
+        (tmp_path / "My Model-abcdef0123.metadata.json").read_text()
+    )
+    assert new_metadata["original_file_name"] == "V1"
+
+    assert (
+        download_manager._active_downloads["dl1"]["file_path"]
+        == new_path.as_posix()
+    )
+
+
+async def test_download_rename_keeps_original_on_conflict(
+    tmp_path: Path, download_manager: DownloadManager
+):
+    _set_template("{model_name}-{hash_short}")
+    model_path = _write_model(tmp_path, "V1", "My Model", "abcdef0123456789")
+    # Conflicting target already exists.
+    (tmp_path / "My Model-abcdef0123.safetensors").write_bytes(b"other")
+
+    downloaded_metadata = [
+        {
+            "file_path": model_path.as_posix(),
+            "file_name": "V1",
+            "model_name": "My Model",
+            "sha256": "abcdef0123456789",
+            "civitai": {"id": 1},
+        }
+    ]
+
+    # Must not raise: a rename conflict never fails the download.
+    await download_manager._apply_download_filename_template(
+        scanner=DummyScanner(tmp_path),
+        model_type="lora",
+        downloaded_metadata=downloaded_metadata,
+        download_id=None,
+    )
+
+    assert model_path.exists()
+
+
+async def test_download_rename_noop_without_template(
+    tmp_path: Path, download_manager: DownloadManager
+):
+    _set_template("")
+    model_path = _write_model(tmp_path, "V1", "My Model", "abcdef0123456789")
+
+    await download_manager._apply_download_filename_template(
+        scanner=DummyScanner(tmp_path),
+        model_type="lora",
+        downloaded_metadata=[{"file_path": model_path.as_posix()}],
+        download_id=None,
+    )
+
+    assert model_path.exists()
+    assert (tmp_path / "V1.metadata.json").exists()