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/.agent/skills/smoke-test/scripts/check_docker.sh

@@ -0,0 +1,80 @@
+#!/usr/bin/env bash
+set -e
+
+echo "=========================================="
+echo "  Checking Docker Environment"
+echo "=========================================="
+echo ""
+
+# Check whether Docker is installed
+if command -v docker >/dev/null 2>&1; then
+    echo "✓ Docker is installed"
+    docker --version
+else
+    echo "✗ Docker is not installed"
+    exit 1
+fi
+echo ""
+
+# Check the Docker daemon
+if docker info >/dev/null 2>&1; then
+    echo "✓ Docker daemon is running normally"
+else
+    echo "✗ Docker daemon is not running"
+    echo "  Please start Docker Desktop or the Docker service"
+    exit 1
+fi
+echo ""
+
+# Check Docker Compose
+if docker compose version >/dev/null 2>&1; then
+    echo "✓ Docker Compose is available"
+    docker compose version
+else
+    echo "✗ Docker Compose is not available"
+    exit 1
+fi
+echo ""
+
+# Check port 2026
+if ! command -v lsof >/dev/null 2>&1; then
+    echo "✗ lsof is required to check whether port 2026 is available"
+    exit 1
+fi
+
+port_2026_usage="$(lsof -nP -iTCP:2026 -sTCP:LISTEN 2>/dev/null || true)"
+if [ -n "$port_2026_usage" ]; then
+    echo "⚠  Port 2026 is already in use"
+    echo "  Occupying process:"
+    echo "$port_2026_usage"
+
+    deerflow_process_found=0
+    while IFS= read -r pid; do
+        if [ -z "$pid" ]; then
+            continue
+        fi
+
+        process_command="$(ps -p "$pid" -o command= 2>/dev/null || true)"
+        case "$process_command" in
+            *[Dd]eer[Ff]low*|*[Dd]eerflow*|*[Nn]ginx*deerflow*|*deerflow/*[Nn]ginx*)
+                deerflow_process_found=1
+                ;;
+        esac
+    done <<EOF
+$(printf '%s\n' "$port_2026_usage" | awk 'NR > 1 {print $2}')
+EOF
+
+    if [ "$deerflow_process_found" -eq 1 ]; then
+        echo "✓ Port 2026 is occupied by DeerFlow"
+    else
+        echo "✗ Port 2026 must be free before starting DeerFlow"
+        exit 1
+    fi
+else
+    echo "✓ Port 2026 is available"
+fi
+echo ""
+
+echo "=========================================="
+echo "  Docker Environment Check Complete"
+echo "=========================================="