fix: logging, warnings, and soft-delete consistency

- Fix duplicate logging in multi-worker mode with file lock for cleanup scheduler
- Add Pydantic V2 model_config to suppress protected_namespaces warning
- Suppress PaddlePaddle ccache warnings
- Fix admin.py using non-existent User.username (now uses email)
- Fix get_user_stats to exclude soft-deleted tasks from statistics
- Fix create_task to exclude soft-deleted tasks from user limit check
- Change LOG_LEVEL default to INFO

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/main.py

@@ -3,6 +3,11 @@ Tool_OCR - FastAPI Application Entry Point (V2)
 Main application setup with CORS, routes, and startup/shutdown events
 """
 
+import warnings
+# Suppress noisy third-party warnings
+warnings.filterwarnings("ignore", message=".*ccache.*")
+warnings.filterwarnings("ignore", message=".*No ccache found.*")
+
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 from contextlib import asynccontextmanager
@@ -107,27 +112,55 @@ def setup_signal_handlers():
 # Ensure log directory exists before configuring logging
 Path(settings.log_file).parent.mkdir(parents=True, exist_ok=True)
 
-# Configure logging - Force configuration to override uvicorn's settings
-logging.basicConfig(
-    level=getattr(logging, settings.log_level),
-    format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
-    handlers=[
-        logging.FileHandler(settings.log_file),
-        logging.StreamHandler(),
-    ],
-    force=True  # Force reconfiguration (Python 3.8+)
-)
+# Configure logging - prevent duplicate handlers
+def setup_logging():
+    """Configure logging with deduplication"""
+    log_level = getattr(logging, settings.log_level, logging.INFO)
+    log_format = "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
 
-# Also explicitly configure root logger and app loggers
-root_logger = logging.getLogger()
-root_logger.setLevel(getattr(logging, settings.log_level))
+    # Get root logger
+    root_logger = logging.getLogger()
 
-# Configure app-specific loggers
-for logger_name in ['app', 'app.services', 'app.services.pdf_generator_service', 'app.services.ocr_service']:
-    app_logger = logging.getLogger(logger_name)
-    app_logger.setLevel(getattr(logging, settings.log_level))
-    app_logger.propagate = True  # Ensure logs propagate to root logger
+    # Clear existing handlers to prevent duplicates
+    root_logger.handlers.clear()
 
+    # Set root level
+    root_logger.setLevel(log_level)
+
+    # Create formatter
+    formatter = logging.Formatter(log_format)
+
+    # File handler
+    file_handler = logging.FileHandler(settings.log_file)
+    file_handler.setLevel(log_level)
+    file_handler.setFormatter(formatter)
+    root_logger.addHandler(file_handler)
+
+    # Stream handler (console)
+    stream_handler = logging.StreamHandler()
+    stream_handler.setLevel(log_level)
+    stream_handler.setFormatter(formatter)
+    root_logger.addHandler(stream_handler)
+
+    # Suppress uvicorn's duplicate access logs
+    logging.getLogger("uvicorn.access").handlers.clear()
+    logging.getLogger("uvicorn.error").handlers.clear()
+
+    # Configure uvicorn loggers to use our handlers
+    for uvi_logger_name in ["uvicorn", "uvicorn.access", "uvicorn.error"]:
+        uvi_logger = logging.getLogger(uvi_logger_name)
+        uvi_logger.handlers.clear()
+        uvi_logger.propagate = True
+        uvi_logger.setLevel(log_level)
+
+    # Configure app-specific loggers (no separate handlers, just propagate)
+    for logger_name in ['app', 'app.services', 'app.routers']:
+        app_logger = logging.getLogger(logger_name)
+        app_logger.handlers.clear()  # Remove any existing handlers
+        app_logger.setLevel(log_level)
+        app_logger.propagate = True  # Propagate to root logger
+
+setup_logging()
 logger = logging.getLogger(__name__)