AgentGate v0.5.0 — DNS sinkhole + SSE live dashboard + hosted team mode

v0.5.0 — DNS sinkhole + live SSE dashboard + hosted team mode

Three big additions expand AgentGate's scope beyond local-only:

1. DNS sinkhole (python -m agentgate.dns_sinkhole)

Zero-config alternative to the mitmproxy proxy for blocking agent egress:

• Spins up a UDP DNS server on 127.0.0.1:5300 (default)
• Returns 0.0.0.0 for denied domains → connection fails fast
• Forwards allowed domains to your real upstream resolver
• Configure AGENTGATE_POLICY and start; no HTTP_PROXY env vars needed

Why DNS instead of eBPF? eBPF requires Linux + clang + libbpf + sudo. DNS interception works on macOS, Linux, and Windows, with zero native dependencies. The tradeoff: cannot block by URL path (only by domain).

2. Live SSE dashboard (/api/events/stream)

The dashboard now pushes new audit events in real time via Server-Sent Events. The browser opens an EventSource, and the server polls the DB every second for rows newer than the last seen id.

On a deny, the page border flashes red and (with permission) a desktop notification fires. No build tools, no React — vanilla JS embedded in the single HTML page.

3. Hosted team mode (pull-policy, push-events)

For teams that want a central source of truth:

• agentgate pull-policy --out policy.hosted.yaml downloads the canonical policy from your team endpoint
• agentgate push-events --db audit.db uploads new audit rows to the central collector
• Auth via AGENTGATE_HOSTED_TOKEN (bearer token)
• Cursor-based sync — only new rows are uploaded

The hosted protocol is plain HTTP so any backend (FastAPI, Cloudflare Worker, Lambda) can host the policy/event endpoints.

Tests

78 → 83 unit tests. New:

• tests/test_dns.py (6 tests)
• tests/test_dashboard_sse.py (1 end-to-end)
• tests/test_hosted.py (5 tests with in-process HTTP server)

Verify script

Still 10 end-to-end steps; CI runs pytest + e2e on Py 3.12 + 3.13.