What does this PR do?

Fixes WeCom outbound local media loading so file:// and plain local path sources are resolved and checked before read_bytes(). Local media uploads are now limited to Hermes media cache directories and the system temp directory, which blocks arbitrary local file reads while preserving generated/cached media delivery.

HTTP/HTTPS media sources still use the existing _download_remote_bytes() path with tools.url_safety.is_safe_url() SSRF protection.

I found this while following up on the OpenClaw/Hermes runtime and security-hardening work after the Oracle zip contribution, and kept the patch intentionally narrow to the public WeCom issue.

Related Issue

Fixes #8733

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• gateway/platforms/wecom.py: add a resolved allowlist for outbound local media roots: image/audio/video/document caches plus tempfile.gettempdir().
• gateway/platforms/wecom.py: validate every local/file URL outbound media source before existence checks and read_bytes().
• gateway/platforms/wecom.py: reject non-local file://host/... media URLs.
• tests/gateway/test_wecom.py: cover allowed media-cache files, blocked arbitrary local files, and symlink escape attempts.

How to Test

1. scripts/run_tests.sh tests/gateway/test_wecom.py
2. git diff --check
3. .venv/bin/python -m ruff check gateway/platforms/wecom.py tests/gateway/test_wecom.py
4. .venv/bin/python -m py_compile gateway/platforms/wecom.py tests/gateway/test_wecom.py

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):)
• I searched for existing PRs to make sure this isn't a duplicate
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes
• I've tested on my platform: macOS Darwin 25.3.0 arm64, Python 3.11.13

Focused WeCom tests and touched-file checks passed; full pytest tests/ -q was not run because this is a narrow platform-adapter fix.

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — N/A
• I've updated cli-config.yaml.example if I added/changed config keys — N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — N/A
• I've considered cross-platform impact per the compatibility guide
• I've updated tool descriptions/schemas if I changed tool behavior — N/A

For New Skills

N/A

Screenshots / Logs

scripts/run_tests.sh tests/gateway/test_wecom.py
45 passed in 3.46s

.venv/bin/python -m ruff check gateway/platforms/wecom.py tests/gateway/test_wecom.py
All checks passed!

git diff --check
# no output

.venv/bin/python -m py_compile gateway/platforms/wecom.py tests/gateway/test_wecom.py
# no output