Fix delay latency minimum: ubridge rejects latency <= 0

Align validation rules with ubridge source: delay latency must be > 0
(packet_filter.c delay_setup line 182). Update FILTERS definition in
link.py and test cases accordingly.

gns3server/controller/link.py

@@ -48,7 +48,7 @@ FILTERS = [
         "name": "Delay",
         "description": "Delay packets in milliseconds. You can add jitter in milliseconds (+/-) of the delay",
         "parameters": [
-            {"name": "Latency", "minimum": 0, "maximum": 32767, "unit": "ms", "type": "int"},
+            {"name": "Latency", "minimum": 1, "maximum": 32767, "unit": "ms", "type": "int"},
             {"name": "Jitter (-/+)", "minimum": 0, "maximum": 32767, "unit": "ms", "type": "int"},
         ],
     },

gns3server/utils/packet_filter_validation.py

@@ -95,7 +95,7 @@ def validate_filter_parameters(filter_type: str, values: List[Any]) -> None:
         },
         "delay": {
             "params_count": 2,  # latency, jitter
-            "ranges": [(0, 32767), (0, 32767)],
+            "ranges": [(1, 32767), (0, 32767)],  # ubridge rejects latency <= 0
             "names": ["Latency", "Jitter"],
             "units": ["ms", "ms"]
         },

tests/utils/test_packet_filter_validation.py

@@ -54,19 +54,23 @@ class TestPacketFilterValidation:
 
     def test_delay_valid(self):
         """Test valid delay parameters."""
-        # Valid range: 0-32767ms
-        validate_filter_parameters("delay", [0, 0])
+        # Valid range: 1-32767ms latency, 0-32767ms jitter
+        validate_filter_parameters("delay", [1, 0])
         validate_filter_parameters("delay", [100, 50])
         validate_filter_parameters("delay", [32767, 32767])
 
     def test_delay_invalid(self):
         """Test invalid delay parameters."""
+        # Zero latency (ubridge rejects latency <= 0)
+        with pytest.raises(FilterValidationError, match="between 1 and 32767"):
+            validate_filter_parameters("delay", [0, 0])
+
         # Negative latency
-        with pytest.raises(FilterValidationError, match="between 0 and 32767"):
+        with pytest.raises(FilterValidationError, match="between 1 and 32767"):
             validate_filter_parameters("delay", [-1, 0])
 
         # Over max
-        with pytest.raises(FilterValidationError, match="between 0 and 32767"):
+        with pytest.raises(FilterValidationError, match="between 1 and 32767"):
             validate_filter_parameters("delay", [32768, 0])
 
         # Negative jitter