Add optional automatic check cycle (clear queue -> scan FIPs -> wait -> repeat)

An admin-controlled scenario that repeats what the operator does by hand:
clear the IP queue, scan and enqueue all free Floating IPs, wait until every
queued address reaches a terminal state (so results are in the Registry),
then wait a configurable interval and start over.

- control-api: new auto_cycle singleton table (migration 0008) holding
  enabled/interval/max-run settings and persisted phase state, so the cycle
  survives restarts; engine in orchestrator/autocycle.go driven from the
  existing loop tick with an injectable "now" for deterministic tests.
- Interval (default 1h, min 60s) and max wait (default unlimited, timeout
  outcome) are runtime settings, never hardcoded.
- The periodic fip_scan_interval_seconds scan is skipped while the cycle is
  enabled. An emptied queue mid-cycle counts as finished; stopping during
  the pause keeps the last cycle's outcome.
- API: GET/PUT /api/v1/admin/auto-cycle, POST .../start, POST .../stop.
- admin-dashboard: "Автоматический цикл" panel on /settings and an
  "Автоцикл активен" indicator on /overview.
- Tests for db, orchestrator, httpapi and dashboard; run-local-e2e.sh now
  exercises a full auto cycle; docs updated; bin/ rebuilt with refreshed
  SHA256SUMS.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/openstack/mock.go

@@ -18,6 +18,10 @@ type MockClient struct {
 	// a specific floating-IP ID on its next call, to exercise retry paths.
 	AssociateFailures    map[string]error
 	DisassociateFailures map[string]error
+
+	// ListFailure, when non-nil, is returned by every ListFloatingIPs call
+	// until the test resets it to nil — to exercise the scan-error path.
+	ListFailure error
 }
 
 func NewMockClient() *MockClient {
@@ -59,6 +63,9 @@ func (m *MockClient) GetFloatingIPByAddress(ctx context.Context, address string)
 func (m *MockClient) ListFloatingIPs(ctx context.Context) ([]FloatingIP, error) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
+	if m.ListFailure != nil {
+		return nil, m.ListFailure
+	}
 	out := make([]FloatingIP, 0, len(m.fips))
 	for _, f := range m.fips {
 		out = append(out, *f)