### What problem does this PR solve?
Fix ingestion pipeline
Only 1 file is acceptable for ingestion pipeline.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### Closes: #12921
### What problem does this PR solve?
Previously, multi-file upload was not working correctly across the
application:
- **Chat**: UI displayed "Upload max 5 files" but only the first file
was actually uploaded
- **Agent conversational mode**: Frontend sent multiple files but
backend only processed one
- **Agent task-mode file inputs**: Explicitly limited to single file
only
This PR enables proper multi-file upload support for both chat and agent
workflows, allowing users to upload and process multiple files (up to 5)
as the UI originally suggested.
**Changes:**
- `web/src/pages/next-chats/hooks/use-upload-file.ts`: Process all files
instead of only `files[0]`
- `api/apps/canvas_app.py`: Handle multiple files via
`files.getlist("file")`
- `web/src/pages/agent/debug-content/uploader.tsx`: Allow up to 5 files
with `multiple={true}`
- `agent/component/begin.py` & `fillup.py`: Support file arrays while
maintaining backward compatibility
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Fix: If the agent debug sheet contains too much content, some of it will
not be displayed. #12974
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Feat: Add a think button to the chat box. #12742
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Support Markdown Rendering for tips in user-fill-up Component
#11825
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Delete useless request hooks. #10427
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Delete useless knowledge base, chat, and search files. #10427
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Adjust the style of the agent canvas connection line #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Support uploading files when running agent #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Fix: Fixed the issue where the debug form Switch component had no
default value #3221
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Feat: In a dialog message, users can enter different types of data #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Fixed the issue where the begin operator parameters could not be
submitted during debugging #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Create empty agent #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Add RunSheet component #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Add FormDrawer to agent page. #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
