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.

services/cms-service/migrations/20260417000001_background_tasks_zip_rag.sql

@@ -0,0 +1,23 @@
+CREATE TABLE IF NOT EXISTS background_tasks (
+    id UUID PRIMARY KEY,
+    organization_id UUID NOT NULL,
+    created_by UUID NOT NULL,
+    title TEXT NOT NULL,
+    course_title TEXT,
+    task_type VARCHAR(64) NOT NULL,
+    status VARCHAR(20) NOT NULL DEFAULT 'queued',
+    progress INTEGER NOT NULL DEFAULT 0,
+    total_items INTEGER NOT NULL DEFAULT 0,
+    processed_items INTEGER NOT NULL DEFAULT 0,
+    failed_items INTEGER NOT NULL DEFAULT 0,
+    error_message TEXT,
+    metadata JSONB NOT NULL DEFAULT '{}'::jsonb,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_background_tasks_org_status_updated
+    ON background_tasks (organization_id, status, updated_at DESC);
+
+CREATE INDEX IF NOT EXISTS idx_background_tasks_type_status
+    ON background_tasks (task_type, status);