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/packages/harness/deerflow/config/acp_config.py

@@ -0,0 +1,51 @@
+"""ACP (Agent Client Protocol) agent configuration loaded from config.yaml."""
+
+import logging
+from collections.abc import Mapping
+
+from pydantic import BaseModel, Field
+
+logger = logging.getLogger(__name__)
+
+
+class ACPAgentConfig(BaseModel):
+    """Configuration for a single ACP-compatible agent."""
+
+    command: str = Field(description="Command to launch the ACP agent subprocess")
+    args: list[str] = Field(default_factory=list, description="Additional command arguments")
+    env: dict[str, str] = Field(default_factory=dict, description="Environment variables to inject into the agent subprocess. Values starting with $ are resolved from host environment variables.")
+    description: str = Field(description="Description of the agent's capabilities (shown in tool description)")
+    model: str | None = Field(default=None, description="Model hint passed to the agent (optional)")
+    auto_approve_permissions: bool = Field(
+        default=False,
+        description=(
+            "When True, DeerFlow automatically approves all ACP permission requests from this agent "
+            "(allow_once preferred over allow_always). When False (default), all permission requests "
+            "are denied — the agent must be configured to operate without requesting permissions."
+        ),
+    )
+
+
+_acp_agents: dict[str, ACPAgentConfig] = {}
+
+
+def get_acp_agents() -> dict[str, ACPAgentConfig]:
+    """Get the currently configured ACP agents.
+
+    Returns:
+        Mapping of agent name -> ACPAgentConfig.  Empty dict if no ACP agents are configured.
+    """
+    return _acp_agents
+
+
+def load_acp_config_from_dict(config_dict: Mapping[str, Mapping[str, object]] | None) -> None:
+    """Load ACP agent configuration from a dictionary (typically from config.yaml).
+
+    Args:
+        config_dict: Mapping of agent name -> config fields.
+    """
+    global _acp_agents
+    if config_dict is None:
+        config_dict = {}
+    _acp_agents = {name: ACPAgentConfig(**cfg) for name, cfg in config_dict.items()}
+    logger.info("ACP config loaded: %d agent(s): %s", len(_acp_agents), list(_acp_agents.keys()))