Remove duplicate folder scanning feature

Delete folder_rename_service.py. Stub out get_duplicate_folders API to return
empty response. Update folder_scan_service and tests to skip rename step.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/server/services/scheduler/__init__.py

@@ -19,6 +19,4 @@ __all__ = [
     "SchedulerServiceError",
     "get_scheduler_service",
     "reset_scheduler_service",
-    # Sub-services (still in scheduler folder)
-    "folder_rename_service",
 ]

src/server/services/scheduler/folder_rename_service.py

@@ -1,33 +0,0 @@
-"""Stub module for folder_rename_service (removed)."""
-
-from typing import Any, Dict, List
-
-
-def _scan_for_pre_existing_duplicates(anime_dir: str) -> List[Any]:
-    """Stub: returns empty list as folder_rename_service was removed.
-    
-    Args:
-        anime_dir: Unused.
-        
-    Returns:
-        Empty list.
-    """
-    return []
-
-
-def validate_and_rename_series_folders(
-    anime_dir: str,
-    dry_run: bool = False,
-    background_loader: Any = None
-) -> Dict[str, int]:
-    """Stub: returns empty stats as folder_rename_service was removed.
-    
-    Args:
-        anime_dir: Unused.
-        dry_run: Unused.
-        background_loader: Unused.
-        
-    Returns:
-        Empty stats dict.
-    """
-    return {"scanned": 0, "renamed": 0, "skipped": 0, "errors": 0}

src/server/services/scheduler/folder_scan_service.py

@@ -85,19 +85,8 @@ class FolderScanService:
             logger.info("NFO repair scan skipped — NFO service removed")
 
             # 1.4 — Validate and rename series folders after NFO repair.
-            # Note: folder_rename_service removed - now a stub that does nothing
-            logger.info("Starting folder rename validation")
-            from src.server.services.scheduler.folder_rename_service import (
-                validate_and_rename_series_folders,
-            )
-            rename_stats = await validate_and_rename_series_folders()
-            logger.info(
-                "Folder rename validation complete",
-                scanned=rename_stats["scanned"],
-                renamed=rename_stats["renamed"],
-                skipped=rename_stats["skipped"],
-                errors=rename_stats["errors"],
-            )
+            # Note: folder_rename_service removed - skip entirely
+            logger.info("Folder rename validation skipped — service removed")
 
             # 1.5 — Check and download missing poster.jpg files.
             logger.info("Starting poster check")