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/distributed_results/v9_chunk_000000_spec.json

@@ -0,0 +1,68 @@
+{
+  "chunk_id": "v9_chunk_000000",
+  "chunk_start": 0,
+  "chunk_end": 2000,
+  "grid": {
+    "flip_thresholds": [
+      0.4,
+      0.5,
+      0.6,
+      0.7
+    ],
+    "ma_gaps": [
+      0.2,
+      0.3,
+      0.4,
+      0.5
+    ],
+    "adx_mins": [
+      18,
+      21,
+      24,
+      27
+    ],
+    "long_pos_maxs": [
+      60,
+      65,
+      70,
+      75
+    ],
+    "short_pos_mins": [
+      20,
+      25,
+      30,
+      35
+    ],
+    "cooldowns": [
+      1,
+      2,
+      3,
+      4
+    ],
+    "position_sizes": [
+      10000
+    ],
+    "tp1_multipliers": [
+      2.0
+    ],
+    "tp2_multipliers": [
+      4.0
+    ],
+    "sl_multipliers": [
+      3.0
+    ],
+    "tp1_close_percents": [
+      60
+    ],
+    "trailing_multipliers": [
+      1.5
+    ],
+    "vol_mins": [
+      1.0
+    ],
+    "max_bars_list": [
+      500
+    ]
+  },
+  "num_workers": 32
+}