Initial commit: hardened DeerFlow factory

Vendored deer-flow upstream (bytedance/deer-flow) plus prompt-injection
hardening:

- New deerflow.security package: content_delimiter, html_cleaner,
  sanitizer (8 layers — invisible chars, control chars, symbols, NFC,
  PUA, tag chars, horizontal whitespace collapse with newline/tab
  preservation, length cap)
- New deerflow.community.searx package: web_search, web_fetch,
  image_search backed by a private SearX instance, every external
  string sanitized and wrapped in <<<EXTERNAL_UNTRUSTED_CONTENT>>>
  delimiters
- All native community web providers (ddg_search, tavily, exa,
  firecrawl, jina_ai, infoquest, image_search) replaced with hard-fail
  stubs that raise NativeWebToolDisabledError at import time, so a
  misconfigured tool.use path fails loud rather than silently falling
  back to unsanitized output
- Native client back-doors (jina_client.py, infoquest_client.py)
  stubbed too
- Native-tool tests quarantined under tests/_disabled_native/
  (collect_ignore_glob via local conftest.py)
- Sanitizer Layer 7 fix: only collapse horizontal whitespace, preserve
  newlines and tabs so list/table structure survives
- Hardened runtime config.yaml references only the searx-backed tools
- Factory overlay (backend/) kept in sync with deer-flow tree as a
  reference / source

See HARDENING.md for the full audit trail and verification steps.

deer-flow/backend/app/gateway/routers/models.py

@@ -0,0 +1,116 @@
+from fastapi import APIRouter, HTTPException
+from pydantic import BaseModel, Field
+
+from deerflow.config import get_app_config
+
+router = APIRouter(prefix="/api", tags=["models"])
+
+
+class ModelResponse(BaseModel):
+    """Response model for model information."""
+
+    name: str = Field(..., description="Unique identifier for the model")
+    model: str = Field(..., description="Actual provider model identifier")
+    display_name: str | None = Field(None, description="Human-readable name")
+    description: str | None = Field(None, description="Model description")
+    supports_thinking: bool = Field(default=False, description="Whether model supports thinking mode")
+    supports_reasoning_effort: bool = Field(default=False, description="Whether model supports reasoning effort")
+
+
+class ModelsListResponse(BaseModel):
+    """Response model for listing all models."""
+
+    models: list[ModelResponse]
+
+
+@router.get(
+    "/models",
+    response_model=ModelsListResponse,
+    summary="List All Models",
+    description="Retrieve a list of all available AI models configured in the system.",
+)
+async def list_models() -> ModelsListResponse:
+    """List all available models from configuration.
+
+    Returns model information suitable for frontend display,
+    excluding sensitive fields like API keys and internal configuration.
+
+    Returns:
+        A list of all configured models with their metadata.
+
+    Example Response:
+        ```json
+        {
+            "models": [
+                {
+                    "name": "gpt-4",
+                    "display_name": "GPT-4",
+                    "description": "OpenAI GPT-4 model",
+                    "supports_thinking": false
+                },
+                {
+                    "name": "claude-3-opus",
+                    "display_name": "Claude 3 Opus",
+                    "description": "Anthropic Claude 3 Opus model",
+                    "supports_thinking": true
+                }
+            ]
+        }
+        ```
+    """
+    config = get_app_config()
+    models = [
+        ModelResponse(
+            name=model.name,
+            model=model.model,
+            display_name=model.display_name,
+            description=model.description,
+            supports_thinking=model.supports_thinking,
+            supports_reasoning_effort=model.supports_reasoning_effort,
+        )
+        for model in config.models
+    ]
+    return ModelsListResponse(models=models)
+
+
+@router.get(
+    "/models/{model_name}",
+    response_model=ModelResponse,
+    summary="Get Model Details",
+    description="Retrieve detailed information about a specific AI model by its name.",
+)
+async def get_model(model_name: str) -> ModelResponse:
+    """Get a specific model by name.
+
+    Args:
+        model_name: The unique name of the model to retrieve.
+
+    Returns:
+        Model information if found.
+
+    Raises:
+        HTTPException: 404 if model not found.
+
+    Example Response:
+        ```json
+        {
+            "name": "gpt-4",
+            "display_name": "GPT-4",
+            "description": "OpenAI GPT-4 model",
+            "supports_thinking": false
+        }
+        ```
+    """
+    config = get_app_config()
+    model = config.get_model_config(model_name)
+    if model is None:
+        raise HTTPException(status_code=404, detail=f"Model '{model_name}' not found")
+
+    return ModelResponse(
+        name=model.name,
+        model=model.model,
+        display_name=model.display_name,
+        description=model.description,
+        supports_thinking=model.supports_thinking,
+        supports_reasoning_effort=model.supports_reasoning_effort,
+    )