refactor: daemon collectors, thin webui proxies, pure config reads

- move state collectors from lib/state.py to daemon/collectors/ (7
  modules, registration side-effect; daemon/server.py imports the
  package before the first populate())
- webui/api: new daemon_route() decorator factory in common.py
  collapses the try/except daemon-proxy boilerplate in all 8
  blueprints (rules/params/body/transform keep responses identical)
- firewall: interface-coverage invariant — config is the source of
  truth for zone interfaces (absent key = empty, no hands-off
  zones); pure validate_coverage() enforced at save (400) and apply
  (409, force: true overrides), top-level `unmanaged` exemption
- lib: get_config() reads are now pure (no dir creation or writes);
  new lib/bootstrap.py creates runtime dirs and persists the
  one-shot nginx legacy migration at daemon start, after
  system_import (lib.nginx.migrate_config_file)
- lib/common: compute_pending() apply-bookkeeping helper
- daemon: emit_and_refresh() handler helper; refresh_state(bump=) so
  /status/refresh no longer bumps versions (poll/mutation only)
- acme: move --log last so acme.sh never treats a real arg as the
  log-file argument
- docs: AGENTS.md, config.md, state-model.md, api.md updated;
  HARDEN.md dropped (plan implemented); apply-confirm force wording

Tests: 917 passed; ruff check + format clean.

webui/static/hoover/components/applyconfirm.js

@@ -151,7 +151,7 @@ async function openApplyModal(successMsg) {
 <div class="modal-body">${rows}</div>
 ${fwPending ? html`<label style="display:flex;gap:8px;align-items:center;margin-top:12px;cursor:pointer">
 <input type="checkbox" checked=${force} onChange="${(e) => { force = e.target.checked; }}" />
-<span class="text-sm">Force apply <span class="text-muted">— overrides firewall safety guards (e.g. leaving an interface in no zone, or removing https/ssh from the default zone)</span></span>
+<span class="text-sm">Force apply <span class="text-muted">— overrides firewall safety guards (e.g. removing an interface from all zones, or removing https/ssh from the default zone)</span></span>
 </label>` : ''}
 <div class="apply-modal-actions"><button class="btn btn-outline" onClick="${() => closeModal()}">Cancel</button><button class="btn btn-primary" onClick="${() => doApply(successMsg, force)}">Apply All</button></div>
 </div>`);