### What problem does this PR solve?
This PR integrates SearXNG as a new search tool for Agents. It adds
corresponding form/config UI on the frontend and a new tool
implementation on the backend, enabling aggregated web searches via a
self-hosted SearXNG instance within chats/workflows. It also adds
multilingual copy to support internationalized presentation and
configuration guidance.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What’s Changed
- Frontend: new SearXNG tool configuration, forms, and command wiring
- Main changes under `web/src/pages/agent/`
- New components and form entries are connected to Agent tool selection
and workflow node configuration
- Backend: new tool implementation
- `agent/tools/searxng.py`: connects to a SearXNG instance and performs
search based on the provided instance URL and query parameters
- i18n updates
- Added/updated keys under `web/src/locales/`: `searXNG` and
`searXNGDescription`
- English reference in
[web/src/locales/en.ts](cci:7://file:///c:/Users/ruy_x/Work/CRSC/2025/Software_Development/2025.8/ragflow-pr/ragflow/web/src/locales/en.ts:0:0-0:0):
- `searXNG: 'SearXNG'`
- `searXNGDescription: 'A component that searches via your provided
SearXNG instance URL. Specify TopN and the instance URL.'`
- Other languages have `searXNG` and `searXNGDescription` added as well,
but accuracy is only guaranteed for English, Simplified Chinese, and
Traditional Chinese.
---------
Co-authored-by: xurui <xurui@crscd.com.cn>
### What problem does this PR solve?
Feat: Limit the appearance of loops in operators in the agent canvas
#3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Fix: Fixed the issue where numbers could not be displayed in the numeric
input box under white theme #3221
Fix: Set the maximum number of rounds for the agent to 1 #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Fix: Fixed the issue that the condition of deleting the classification
operator cannot be connected anymore #3221
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Feat: Modify the agent tool name #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Use the message_id returned by the interface as the id of the
reply message #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: The delete button is displayed only when the cursor is hovered
over the connection line #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Add Tavily operator #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Connect conditional operators to other operators #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Add agent operator node from agent form #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Add DynamicPrompt component #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Add AgentNode component #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Switching the programming language of the code operator will
switch the corresponding language template #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 page would refresh continuously when
opening the sheet on the right side of the canvas #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Migrate the code operator to the new agent. #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Use react-hook-form to synchronize the data of the categorize form
to the agent node. #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Render agent details #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
