feat: Implement ZIP RAG import functionality with background processing

- Added support for ZIP RAG import in the asset management system.
- Introduced a new background task type for ZIP RAG imports.
- Enhanced the asset import process to allow for optional development processing.
- Updated the UI to reflect the new RAG processing status and options.
- Created database migration for background tasks related to ZIP RAG imports.
- Refactored asset handling to support FLV normalization and improved error handling.
- Added new API endpoints and updated existing ones to accommodate changes.

.env.dev.example

@@ -54,6 +54,8 @@ SAM_DATABASE_URL=mysql://user:password@host:3306/sige_sam_v3
 LOCAL_VIDEO_BRIDGE_URL=http://localhost:8000
 EMBEDDING_MODEL=nomic-embed-text
 LOCAL_LLM_MODEL=llama3.2:3b
+# Workers para procesamiento RAG asíncrono post-ZIP ("túneles"): 1..12
+ZIP_RAG_CONCURRENCY=5
 
 # Backend-to-backend (LMS -> CMS)
 CMS_API_URL=http://studio:3001