Refactor downloader and file manager for improved rclone integration and add healthcheck and smoke test options

- Renamed download flags in ContentDownloader for clarity.
- Enhanced FileManager with methods to build upload paths and verify existing files for rclone uploads.
- Updated StreamProcessor to return success status for stream processing.
- Added rclone smoke test and healthcheck functions to validate configuration and tool availability.
- Improved environment variable handling with a utility function.
- Updated TwitchArchive to incorporate new rclone verification and processing logic.
- Added unit tests for new functionality and refactored existing tests for clarity and coverage.

Co-authored-by: Copilot <copilot@github.com>

modules/recorder.py

@@ -7,6 +7,8 @@ import subprocess
 from typing import Dict, Any, Optional
 from colorama import Fore, Style
 
+from .utils import get_env_value
+
 
 class StreamRecorder:
     """Handles live stream recording using streamlink."""
@@ -68,7 +70,7 @@ class StreamRecorder:
             print(f'{Fore.YELLOW}  Consider disabling streamlink_ttvlol in config or using alternative methods{Style.RESET_ALL}')
         
         # Add authentication if available
-        oauth_token = os.getenv("OAUTH-PRIVATE-TOKEN", "")
+        oauth_token = get_env_value("OAUTH-PRIVATE-TOKEN", "OAUTH_PRIVATE_TOKEN", default="")
         if oauth_token and oauth_token != "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx":
             cmd.extend(['--twitch-api-header', f'Authorization=OAuth {oauth_token}'])