### What problem does this PR solve?
issue:
https://github.com/infiniflow/ragflow/issues/10427
change:
new component variable assigner
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Add mechanism to check cancellation in Agent.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
#9082#6365
<u> **WARNING: it's not compatible with the older version of `Agent`
module, which means that `Agent` from older versions can not work
anymore.**</u>
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
