Feat(browser control)：Add new agent component 'browser' to control browser by AI (#14888)

### What problem does this PR solve?
This PR adds a new `Browser` operator to Agent workflows, enabling
prompt-driven browser automation in RAGFlow.Technically based
‘Browser-Use’

It includes:
- Backend browser component execution with tenant LLM integration
- Upload source support (file IDs, URLs, variables, CSV/JSON array)
- Downloaded file persistence to RAGFlow storage
- Frontend node/operator integration, form config, icon, and i18n
updates
- Unit tests for upload/download and ID parsing logic
- Dependency and Docker updates for browser-use runtime support

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

web/src/constants/agent.tsx

@@ -109,6 +109,7 @@ export enum Operator {
   StringTransform = 'StringTransform',
   SearXNG = 'SearXNG',
   DocGenerator = 'DocGenerator',
+  Browser = 'Browser',
   Placeholder = 'Placeholder',
   DataOperations = 'DataOperations',
   ListOperations = 'ListOperations',