copilot: log into devices using the node default credentials

The vendored gns3fy Node model dropped default_username/default_password
from the API response, and the nornir groups hardcoded empty
credentials, so drivers that require authentication (gns3_ruijie_telnet,
stock netmiko SSH/telnet) could not log in.

Carry the per-node credentials through nodes_inventory() into the
nornir hosts data at host level, where they override the group's empty
fallback. Missing or cleared ("") values keep inheriting from the
group, so no-auth drivers are unaffected.

gns3server/agent/gns3_copilot/gns3_client/custom_gns3fy.py

@@ -1372,6 +1372,8 @@ class Node:
     properties: Any | None = None
     tags: list[str] | None = None
     netmiko_device_type: str | None = None
+    default_username: str | None = None
+    default_password: str | None = None
 
     template: str | None = None
     links: list[Link] = field(default_factory=list, repr=False)
@@ -2489,6 +2491,8 @@ class Project:
                         "y": _n.y,
                         "tags": _n.tags if _n.tags else [],
                         "netmiko_device_type": _n.netmiko_device_type,
+                        "default_username": _n.default_username,
+                        "default_password": _n.default_password,
                     }
                 }
             )

gns3server/agent/gns3_copilot/utils/get_gns3_device_port.py

@@ -160,7 +160,7 @@ def get_device_ports_from_topology(
             # This is the Nornir best practice - each host has its own
             # connection configuration (device_type), while sharing common
             # settings (hostname, timeout) via group inheritance.
-            hosts_data[device_name] = {
+            host_entry = {
                 "port": node_info["console_port"],
                 "platform": platform,
                 "groups": ["network_devices"],  # For inheriting hostname, timeout, etc.
@@ -171,6 +171,16 @@ def get_device_ports_from_topology(
                 },
             }
 
+            # Per-node default credentials (seeded from the template appliance
+            # metadata) override the group's empty fallback. Only inject when
+            # set, so credential-less devices keep inheriting the group values.
+            if node_info.get("default_username"):
+                host_entry["username"] = node_info["default_username"]
+            if node_info.get("default_password"):
+                host_entry["password"] = node_info["default_password"]
+
+            hosts_data[device_name] = host_entry
+
         logger.info("Returning %d device port mappings", len(hosts_data))
 
         return hosts_data