feat: Add comprehensive JSON debug logging system

Implements a complete structured logging system for troubleshooting and service development.

Features:
- Binary toggle via --debug flag or debug: true in config
- JSON Lines (.jsonl) format for easy parsing and analysis
- Comprehensive logging of all operations:
  * Session info (version, platform, Python version)
  * CLI parameters and service configuration
  * CDM details (Widevine/PlayReady, security levels)
  * Authentication status
  * Title and track metadata
  * DRM operations (PSSH, KIDs, license requests)
  * Vault queries with key retrieval
  * Full error traces with context

- Configurable key logging via debug_keys option
- Smart redaction (passwords, tokens, cookies always redacted)
- Error logging for all critical operations:
  * Authentication failures
  * Title fetching errors
  * Track retrieval errors
  * License request failures (Widevine & PlayReady)
  * Vault operation errors

- Removed old text logging system

unshackle/core/config.py

@@ -31,6 +31,7 @@ class Config:
     class _Filenames:
         # default filenames, do not modify here, set via config
         log = "unshackle_{name}_{time}.log"  # Directories.logs
+        debug_log = "unshackle_debug_{service}_{time}.jsonl"  # Directories.logs
         config = "config.yaml"  # Directories.services / tag
         root_config = "unshackle.yaml"  # Directories.user_configs
         chapters = "Chapters_{title}_{random}.txt"  # Directories.temp
@@ -98,6 +99,9 @@ class Config:
         self.title_cache_max_retention: int = kwargs.get("title_cache_max_retention", 86400)  # 24 hours default
         self.title_cache_enabled: bool = kwargs.get("title_cache_enabled", True)
 
+        self.debug: bool = kwargs.get("debug", False)
+        self.debug_keys: bool = kwargs.get("debug_keys", False)
+
     @classmethod
     def from_yaml(cls, path: Path) -> Config:
         if not path.exists():