feat: declare collection cadence and preserve Agent sampling timestamps

plugin/manifest.json

@@ -1,7 +1,7 @@
 {
   "id": "pigway-agent",
   "name": "PIGWay Raspberry Pi Agent",
-  "version": "1.2.2",
+  "version": "1.3.0",
   "protocol_version": 1,
   "entrypoint": "worker.py",
   "runtime": "python3",
@@ -38,5 +38,8 @@
     "contract": "console-ui-v1",
     "entrypoint": "ui/index.js"
   },
-  "legacy_connection_fields": true
+  "legacy_connection_fields": true,
+  "collection": {
+    "interval_seconds": 1
+  }
 }

plugin/worker.py

@@ -80,9 +80,15 @@ def collect(device):
         rate = value.get('network', {}).get(field)
         if isinstance(rate, (int, float)) and not isinstance(rate, bool) and math.isfinite(rate) and rate >= 0:
             metrics.append({'resource_id': 'host', 'key': key, 'value': rate, 'unit': 'bytes_per_second'})
+    for metric in metrics:
+        source = value.get('network', {}) if metric['key'].startswith('network_') else value.get('system', {})
+        at = source.get('observed_at') if metric['key'] != 'uptime_seconds' else value.get('timestamp')
+        if isinstance(at, (int, float)) and not isinstance(at, bool) and math.isfinite(at) and at > 0:
+            metric['observed_at'] = at
     return {'schema_version': 1, 'observed_at': value.get('timestamp'),
             'identity': {'reported_name': value['machine'].get('name'), 'category': 'host',
                          'details': value.get('device', {})},
+            'collection': value.get('collection', MANIFEST['collection']),
             'capabilities': MANIFEST['capabilities'], 'metrics': metrics,
             'resources': [{'id': 'host', 'type': 'host'}],
             'alerts': value.get('display', {}).get('alerts', []),