fix: ReccoBeats audio features and OpenAI narrative generation

- Add reccobeats_id column to Track model for API mapping
- Fix ReccoBeats batch size limit (max 40 IDs per request)
- Extract spotify_id from href field in ReccoBeats responses
- Fix OpenAI API: remove unsupported temperature param, increase max_completion_tokens to 4000
- Add playlist/user management methods to spotify_client for future auto-playlist feature

backend/app/services/narrative_service.py

@@ -73,8 +73,7 @@ class NarrativeService:
                 {"role": "user", "content": prompt},
             ],
             response_format={"type": "json_object"},
-            max_completion_tokens=1500,
-            temperature=0.8,
+            max_completion_tokens=4000,
         )
         return self._clean_and_parse_json(response.choices[0].message.content)