feat(api): add tag filtering to nodes and templates endpoints

- Add optional `tags` query parameter to `/nodes` and `/templates` endpoints
- Support filtering by tags in format "key:value" with multiple tags ANDed together
- Example: `?tags=vendor:cisco&tags=model:7200` filters nodes/templates with both tags
- Maintain backward compatibility for existing API usage without tags parameter

gns3server/controller/node.py

@@ -97,6 +97,7 @@ class Node:
         self._y = 0
         self._z = 1  # default z value is 1
         self._locked = False
+        self._tags = {}
         self._ports = None
         self._symbol = None
         self._custom_adapters = []
@@ -218,6 +219,17 @@ class Node:
     def properties(self, val):
         self._properties = val
 
+    @property
+    def tags(self):
+        return self._tags
+
+    @tags.setter
+    def tags(self, val):
+        if isinstance(val, dict):
+            self._tags = val
+        else:
+            self._tags = {}
+
     def _base_config_file_content(self, path):
         if not os.path.isabs(path):
             path = os.path.join(self.project.controller.configs_path(), path)
@@ -823,6 +835,7 @@ class Node:
                 "port_segment_size": self._port_segment_size,
                 "first_port_name": self._first_port_name,
                 "custom_adapters": self._custom_adapters,
+                "tags": self._tags,
         }
 
         if topology_dump: