feat(pool): add start_index so manual and auto pools can coexist

Production had two disjoint tmux pools named alike but for different
purposes:
  ccl-0..ccl-9           — manual/interactive sessions (operator)
  ccl-auto-11..ccl-auto-20 — autonomous dispatcher pool

Until now the daemon's loops iterated prefix + 0..Max, so with the
deployed config ("prefix: ccl-auto", min=2, max=10) the dispatcher
looked for sessions "ccl-auto0..ccl-auto9" that never existed, while
the real auto pool ccl-auto-11..20 was invisible. Net effect: no task
was ever dispatched, and killAllPoolSessions fabricated phantom
"ccl-auto0/1" sessions on each swap.

- AutonomousConfig gains StartIndex (yaml start_index, default 0).
  Behaviour is unchanged when StartIndex is 0.
- Monitor, switcher (kill + recreate), dispatcher (findFreeSession),
  and lifecycle (EnsureAll + reconcile) all iterate
  [StartIndex, StartIndex+Max) so the daemon only touches its own
  range and leaves ccl-0..ccl-9 alone.
- Production config updated to prefix: "ccl-auto-", start_index: 11,
  min: 10, max: 10 — covering the 10 real ccl-auto-11..20 sessions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/quota/monitor.go

@@ -140,7 +140,8 @@ func (m *Monitor) poll() {
 	if prefix == "" {
 		prefix = "ccl-auto-"
 	}
-	for i := 0; i < m.config.Pool.Autonomous.Max; i++ {
+	start := m.config.Pool.Autonomous.StartIndex
+	for i := start; i < start+m.config.Pool.Autonomous.Max; i++ {
 		name := sessionName(prefix, i)
 		if !m.tmux.HasSession(name) {
 			continue