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

app/api/cluster/control/route.ts

@@ -0,0 +1,74 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { exec } from 'child_process'
+import { promisify } from 'util'
+
+const execAsync = promisify(exec)
+
+export const dynamic = 'force-dynamic'
+
+export async function POST(request: NextRequest) {
+  try {
+    const { action } = await request.json()
+    
+    if (action === 'start') {
+      // Start the coordinator
+      const startCmd = 'cd /home/icke/traderv4/cluster && nohup python3 distributed_coordinator.py > coordinator.log 2>&1 &'
+      await execAsync(startCmd)
+      
+      // Wait a moment for it to start
+      await new Promise(resolve => setTimeout(resolve, 2000))
+      
+      // Verify it's running
+      const checkCmd = 'ps aux | grep distributed_coordinator | grep -v grep | wc -l'
+      const { stdout } = await execAsync(checkCmd)
+      const isRunning = parseInt(stdout.trim()) > 0
+      
+      return NextResponse.json({
+        success: true,
+        message: isRunning ? 'Coordinator started successfully' : 'Coordinator start initiated',
+        isRunning
+      })
+    } else if (action === 'stop') {
+      // Stop coordinator and workers
+      const stopCmd = 'pkill -9 -f distributed_coordinator; pkill -9 -f distributed_worker'
+      await execAsync(stopCmd)
+      
+      // Wait a moment
+      await new Promise(resolve => setTimeout(resolve, 1000))
+      
+      // Verify it's stopped
+      const checkCmd = 'ps aux | grep -E "(distributed_coordinator|distributed_worker)" | grep -v grep | wc -l'
+      const { stdout } = await execAsync(checkCmd)
+      const processCount = parseInt(stdout.trim())
+      
+      return NextResponse.json({
+        success: true,
+        message: processCount === 0 ? 'Cluster stopped successfully' : 'Stop signal sent',
+        isRunning: processCount > 0
+      })
+    } else if (action === 'status') {
+      // Check if coordinator is running
+      const checkCmd = 'ps aux | grep distributed_coordinator.py | grep -v grep | wc -l'
+      const { stdout } = await execAsync(checkCmd)
+      const isRunning = parseInt(stdout.trim()) > 0
+      
+      return NextResponse.json({
+        success: true,
+        isRunning,
+        message: isRunning ? 'Coordinator is running' : 'Coordinator is not running'
+      })
+    } else {
+      return NextResponse.json({
+        success: false,
+        error: 'Invalid action. Use "start", "stop", or "status"'
+      }, { status: 400 })
+    }
+  } catch (error) {
+    console.error('Error controlling cluster:', error)
+    return NextResponse.json({
+      success: false,
+      error: 'Failed to control cluster',
+      details: error instanceof Error ? error.message : 'Unknown error'
+    }, { status: 500 })
+  }
+}