feat: enhance asset import functionality and unit tracking

- Added WHISPER_URL environment variable to docker-compose for audio transcription service.
- Updated Nginx configuration to increase timeout settings for API requests.
- Enhanced asset ingestion process to extract unit numbers from ZIP entry paths, supporting various naming conventions.
- Implemented logic to split intensive courses into two regular courses during asset import.
- Added new fields to the Asset and QuestionBank models to track unit numbers and source asset links.
- Introduced backward-compatible fallbacks for fetching study plans and courses from legacy MySQL database.
- Improved error handling and progress tracking during ZIP file uploads in the frontend.
- Created a new SQL migration to add unit_number and source_asset_id columns to the assets and question_bank tables, along with necessary indexes for performance.

.env.example

@@ -60,10 +60,14 @@ EXTERNAL_ID_TIPO_NOTA=1
 # AWS S3 Configuration (audio storage)
 # Bucket: openccb-802726101181-us-east-2-an
 # ----------------------------------------
+ASSETS_STORAGE=s3
 AWS_ACCESS_KEY_ID=
 AWS_SECRET_ACCESS_KEY=
 AWS_REGION=us-east-2
 S3_BUCKET=openccb-802726101181-us-east-2-an
+S3_ENDPOINT=
+S3_PUBLIC_BASE_URL=
+S3_FORCE_PATH_STYLE=false
 
 # ----------------------------------------
 # Mercado Pago Configuration