fix: Database-first cluster status detection + Stop button clarification

CRITICAL FIX (Nov 30, 2025):
- Dashboard showed 'idle' despite 22+ worker processes running
- Root cause: SSH-based worker detection timing out
- Solution: Check database for running chunks FIRST

Changes:
1. app/api/cluster/status/route.ts:
   - Query exploration database before SSH detection
   - If running chunks exist, mark workers 'active' even if SSH fails
   - Override worker status: 'offline' → 'active' when chunks running
   - Log: '✅ Cluster status: ACTIVE (database shows running chunks)'
   - Database is source of truth, SSH only for supplementary metrics

2. app/cluster/page.tsx:
   - Stop button ALREADY EXISTS (conditionally shown)
   - Shows Start when status='idle', Stop when status='active'
   - No code changes needed - fixed by status detection

Result:
- Dashboard now shows 'ACTIVE' with 2 workers (correct)
- Workers show 'active' status (was 'offline')
- Stop button automatically visible when cluster active
- System resilient to SSH timeouts/network issues

Verified:
- Container restarted: Nov 30 21:18 UTC
- API tested: Returns status='active', activeWorkers=2
- Logs confirm: Database-first logic working
- Workers confirmed running: 22+ processes on worker1, workers on worker2

sweep_v9_baseline.csv

@@ -0,0 +1,2 @@
+flip_threshold_percent,ma_gap_threshold,momentum_min_adx,momentum_long_max_pos,momentum_short_min_pos,cooldown_bars,momentum_spacing,momentum_cooldown,trades,total_pnl,win_rate,avg_pnl,max_drawdown,profit_factor
+0.6,0.35,23.0,70.0,30.0,3,4,3,569,405.87730598762016,60.98418277680141,0.7133168822278034,-1360.5755690250467,1.021971337907867