feat!: migrate to OpenAI native tool calls and fix circular deps (#fuck-gemini)

- Fix circular dependencies in agent/tools
- Migrate from custom JSON to OpenAI tool calls format
- Add async streaming (step_stream, complete_stream)
- Simplify prompt system and remove token counting
- Add 5 new API endpoints (/health, /v1/models, /api/memory/*)
- Add 3 new tools (get_torrent_by_index, add_torrent_by_index, set_language)
- Fix all 500 tests and add coverage config (80% threshold)
- Add comprehensive docs (README, pytest guide)

BREAKING: LLM interface changed, memory injection via get_memory()

domain/subtitles/repositories.py

@@ -1,6 +1,6 @@
 """Subtitle repository interfaces (abstract)."""
+
 from abc import ABC, abstractmethod
-from typing import List, Optional
 
 from ..shared.value_objects import ImdbId
 from .entities import Subtitle
@@ -10,50 +10,50 @@ from .value_objects import Language
 class SubtitleRepository(ABC):
     """
     Abstract repository for subtitle persistence.
-    
+
     This defines the interface that infrastructure implementations must follow.
     """
-    
+
     @abstractmethod
     def save(self, subtitle: Subtitle) -> None:
         """
         Save a subtitle to the repository.
-        
+
         Args:
             subtitle: Subtitle entity to save
         """
         pass
-    
+
     @abstractmethod
     def find_by_media(
         self,
         media_imdb_id: ImdbId,
-        language: Optional[Language] = None,
-        season: Optional[int] = None,
-        episode: Optional[int] = None
-    ) -> List[Subtitle]:
+        language: Language | None = None,
+        season: int | None = None,
+        episode: int | None = None,
+    ) -> list[Subtitle]:
         """
         Find subtitles for a media item.
-        
+
         Args:
             media_imdb_id: IMDb ID of the media
             language: Optional language filter
             season: Optional season number (for TV shows)
             episode: Optional episode number (for TV shows)
-        
+
         Returns:
             List of matching subtitles
         """
         pass
-    
+
     @abstractmethod
     def delete(self, subtitle: Subtitle) -> bool:
         """
         Delete a subtitle from the repository.
-        
+
         Args:
             subtitle: Subtitle to delete
-        
+
         Returns:
             True if deleted, False if not found
         """