refactor(cache): reorganize cache directory structure with automatic legacy cleanup

- Centralize cache path resolution in new py/utils/cache_paths.py module
- Migrate legacy cache files to organized structure: {settings_dir}/cache/{model|recipe|fts|symlink}/
- Automatically clean up legacy files after successful migration with integrity verification
- Update Config symlink cache to use new path and migrate from old location
- Simplify service classes (PersistentModelCache, PersistentRecipeCache, RecipeFTSIndex, TagFTSIndex) to use centralized migration logic
- Add comprehensive test coverage for cache paths and automatic cleanup

py/services/persistent_model_cache.py

@@ -1,13 +1,12 @@
 import json
 import logging
 import os
-import re
 import sqlite3
 import threading
 from dataclasses import dataclass
 from typing import Dict, List, Mapping, Optional, Sequence, Tuple
 
-from ..utils.settings_paths import get_project_root, get_settings_dir
+from ..utils.cache_paths import CacheType, resolve_cache_path_with_migration
 
 logger = logging.getLogger(__name__)
 
@@ -404,20 +403,12 @@ class PersistentModelCache:
     # Internal helpers -------------------------------------------------
 
     def _resolve_default_path(self, library_name: str) -> str:
-        override = os.environ.get("LORA_MANAGER_CACHE_DB")
-        if override:
-            return override
-        try:
-            settings_dir = get_settings_dir(create=True)
-        except Exception as exc:  # pragma: no cover - defensive guard
-            logger.warning("Falling back to project directory for cache: %s", exc)
-            settings_dir = get_project_root()
-        safe_name = re.sub(r"[^A-Za-z0-9_.-]", "_", library_name or "default")
-        if safe_name.lower() in ("default", ""):
-            legacy_path = os.path.join(settings_dir, self._DEFAULT_FILENAME)
-            if os.path.exists(legacy_path):
-                return legacy_path
-        return os.path.join(settings_dir, "model_cache", f"{safe_name}.sqlite")
+        env_override = os.environ.get("LORA_MANAGER_CACHE_DB")
+        return resolve_cache_path_with_migration(
+            CacheType.MODEL,
+            library_name=library_name,
+            env_override=env_override,
+        )
 
     def _initialize_schema(self) -> None:
         with self._db_lock:

py/services/persistent_recipe_cache.py

@@ -10,13 +10,12 @@ from __future__ import annotations
 import json
 import logging
 import os
-import re
 import sqlite3
 import threading
 from dataclasses import dataclass
 from typing import Dict, List, Optional, Set, Tuple
 
-from ..utils.settings_paths import get_project_root, get_settings_dir
+from ..utils.cache_paths import CacheType, resolve_cache_path_with_migration
 
 logger = logging.getLogger(__name__)
 
@@ -312,20 +311,12 @@ class PersistentRecipeCache:
     # Internal helpers
 
     def _resolve_default_path(self, library_name: str) -> str:
-        override = os.environ.get("LORA_MANAGER_RECIPE_CACHE_DB")
-        if override:
-            return override
-        try:
-            settings_dir = get_settings_dir(create=True)
-        except Exception as exc:
-            logger.warning("Falling back to project directory for recipe cache: %s", exc)
-            settings_dir = get_project_root()
-        safe_name = re.sub(r"[^A-Za-z0-9_.-]", "_", library_name or "default")
-        if safe_name.lower() in ("default", ""):
-            legacy_path = os.path.join(settings_dir, self._DEFAULT_FILENAME)
-            if os.path.exists(legacy_path):
-                return legacy_path
-        return os.path.join(settings_dir, "recipe_cache", f"{safe_name}.sqlite")
+        env_override = os.environ.get("LORA_MANAGER_RECIPE_CACHE_DB")
+        return resolve_cache_path_with_migration(
+            CacheType.RECIPE,
+            library_name=library_name,
+            env_override=env_override,
+        )
 
     def _initialize_schema(self) -> None:
         with self._db_lock:

py/services/recipe_fts_index.py

@@ -15,7 +15,7 @@ import threading
 import time
 from typing import Any, Dict, List, Optional, Set
 
-from ..utils.settings_paths import get_settings_dir
+from ..utils.cache_paths import CacheType, resolve_cache_path_with_migration
 
 logger = logging.getLogger(__name__)
 
@@ -67,17 +67,11 @@ class RecipeFTSIndex:
 
     def _resolve_default_path(self) -> str:
         """Resolve the default database path."""
-        override = os.environ.get("LORA_MANAGER_RECIPE_FTS_DB")
-        if override:
-            return override
-
-        try:
-            settings_dir = get_settings_dir(create=True)
-        except Exception as exc:
-            logger.warning("Falling back to current directory for FTS index: %s", exc)
-            settings_dir = "."
-
-        return os.path.join(settings_dir, self._DEFAULT_FILENAME)
+        env_override = os.environ.get("LORA_MANAGER_RECIPE_FTS_DB")
+        return resolve_cache_path_with_migration(
+            CacheType.RECIPE_FTS,
+            env_override=env_override,
+        )
 
     def get_database_path(self) -> str:
         """Return the resolved database path."""

py/services/tag_fts_index.py

@@ -16,7 +16,7 @@ import time
 from pathlib import Path
 from typing import Dict, List, Optional, Set
 
-from ..utils.settings_paths import get_settings_dir
+from ..utils.cache_paths import CacheType, resolve_cache_path_with_migration
 
 logger = logging.getLogger(__name__)
 
@@ -89,17 +89,11 @@ class TagFTSIndex:
 
     def _resolve_default_db_path(self) -> str:
         """Resolve the default database path."""
-        override = os.environ.get("LORA_MANAGER_TAG_FTS_DB")
-        if override:
-            return override
-
-        try:
-            settings_dir = get_settings_dir(create=True)
-        except Exception as exc:
-            logger.warning("Falling back to current directory for FTS index: %s", exc)
-            settings_dir = "."
-
-        return os.path.join(settings_dir, self._DEFAULT_FILENAME)
+        env_override = os.environ.get("LORA_MANAGER_TAG_FTS_DB")
+        return resolve_cache_path_with_migration(
+            CacheType.TAG_FTS,
+            env_override=env_override,
+        )
 
     def _resolve_default_csv_path(self) -> str:
         """Resolve the default CSV file path."""