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

cluster/test_ssh_commands.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+echo "Testing different SSH command patterns..."
+echo ""
+
+# What coordinator currently does (BROKEN):
+echo "=== Test 1: Single quotes (current) ==="
+ssh root@10.10.254.106 ssh root@10.20.254.100 'echo test1 > /tmp/test1.txt && cat /tmp/test1.txt'
+echo "Exit code: $?"
+echo ""
+
+# What should work (double-nested quotes):
+echo "=== Test 2: Double-nested quotes ==="
+ssh root@10.10.254.106 "ssh root@10.20.254.100 'echo test2 > /tmp/test2.txt && cat /tmp/test2.txt'"
+echo "Exit code: $?"
+echo ""
+
+# Verify which files were created:
+echo "=== Checking which test files exist ==="
+ssh root@10.10.254.106 "ssh root@10.20.254.100 'ls -la /tmp/test*.txt 2>/dev/null || echo \"No test files found\"'"
+