feat: pre-computed state store and async ACME issuance (fixes timeout mismatch)

- Add lib/state.py: in-memory state store with subsystem collectors
  (firewall, dnsmasq, nginx, acme, wireguard)
- Refactor all handlers: read from state on GET, call refresh_state()
  after mutations instead of invoking subprocesses per request
- daemon/server.py: add refresh_state(), /status/all, /status/refresh;
  populate state at startup
- webui/api/certs.py: async step-by-step ACME issuance (validate,
  issue with request_id, poll status) replacing blocking endpoint
- webui/server.py: render pages from state instead of direct lib calls
- Update templates, JS for async cert issuance with polling UI
- Update tests for state-based mocking; add test_state.py
- Fix SIM105 lint issue (contextlib.suppress)
- Add TODO.md with certificate issuance issue tracking

Resolves: WebUI 30s timeout freeze during cert issuance (Problem 1)

tests/test_server.py

@@ -93,5 +93,5 @@ class TestPageRoutes:
     @patch("webui.server.get")
     def test_dashboard_no_crash(self, mock_get, client):
         mock_get.return_value = {}
-        resp = client.get("/")
+        resp = client.get("/dashboard")
         assert resp.status_code == 200