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/frontend/Dockerfile

@@ -0,0 +1,50 @@
+# Frontend Dockerfile
+# Supports two targets:
+#   --target dev   — install deps only, run `pnpm dev` at container start
+#   --target prod  — full build baked in, run `pnpm start` at container start (default if no --target is specified)
+
+ARG PNPM_STORE_PATH=/root/.local/share/pnpm/store
+ARG NPM_REGISTRY
+
+# ── Base: shared setup ────────────────────────────────────────────────────────
+FROM node:22-alpine AS base
+ARG PNPM_STORE_PATH
+ARG NPM_REGISTRY
+# Configure corepack registry before installing pnpm so the download itself
+# succeeds in restricted networks (COREPACK_NPM_REGISTRY controls where
+# corepack fetches package managers from).
+RUN if [ -n "${NPM_REGISTRY}" ]; then \
+      export COREPACK_NPM_REGISTRY="${NPM_REGISTRY}"; \
+    fi && \
+    corepack enable && corepack install -g pnpm@10.26.2
+RUN pnpm config set store-dir ${PNPM_STORE_PATH}
+# Optionally override npm registry for restricted networks (e.g. NPM_REGISTRY=https://registry.npmmirror.com)
+RUN if [ -n "${NPM_REGISTRY}" ]; then pnpm config set registry "${NPM_REGISTRY}"; fi
+WORKDIR /app
+COPY frontend ./frontend
+
+# ── Dev: install only, CMD is overridden by docker-compose ───────────────────
+FROM base AS dev
+RUN cd /app/frontend && pnpm install --frozen-lockfile
+EXPOSE 3000
+
+# ── Builder: install + compile Next.js ───────────────────────────────────────
+FROM base AS builder
+RUN cd /app/frontend && pnpm install --frozen-lockfile
+# Skip env validation — runtime vars are injected by nginx/container
+RUN cd /app/frontend && SKIP_ENV_VALIDATION=1 pnpm build
+
+# ── Prod: minimal runtime with pre-built output ───────────────────────────────
+FROM node:22-alpine AS prod
+ARG PNPM_STORE_PATH
+ARG NPM_REGISTRY
+RUN if [ -n "${NPM_REGISTRY}" ]; then \
+      export COREPACK_NPM_REGISTRY="${NPM_REGISTRY}"; \
+    fi && \
+    corepack enable && corepack install -g pnpm@10.26.2
+RUN pnpm config set store-dir ${PNPM_STORE_PATH}
+RUN if [ -n "${NPM_REGISTRY}" ]; then pnpm config set registry "${NPM_REGISTRY}"; fi
+WORKDIR /app
+COPY --from=builder /app/frontend ./frontend
+EXPOSE 3000
+CMD ["sh", "-c", "cd /app/frontend && pnpm start"]