huge refactor of the entire codebase, with the goal of improving maintainability, readability, and extensibility. This commit includes changes to almost every file in the project, including:

Provider/youtube.py

@@ -21,7 +21,7 @@ class YouTube(TableProviderMixin, Provider):
     - _selection_args: For @N expansion control and download-file routing
     
     SELECTION FLOW:
-    1. User runs: search-file -provider youtube "linux tutorial"
+    1. User runs: search-file -plugin youtube "linux tutorial"
     2. Results show video rows with uploader, duration, views
     3. User selects a video: @1
     4. Selection metadata routes to download-file with the YouTube URL
@@ -121,7 +121,7 @@ class YouTube(TableProviderMixin, Provider):
 
 # Minimal provider registration for the new table system
 try:
-    from SYS.result_table_adapters import register_provider
+    from SYS.result_table_adapters import register_plugin
     from SYS.result_table_api import ResultModel, ColumnSpec, metadata_column, title_column
 
     def _convert_search_result_to_model(sr: Any) -> ResultModel:
@@ -206,7 +206,7 @@ try:
         
         return ["-title", row.title or ""]
 
-    register_provider(
+    register_plugin(
         "youtube",
         _adapter,
         columns=_columns_factory,