Merge branch '3.1' into fix/duplicate-device-configs-merge

Resolve conflicts against the upstream wave (PRs #2952-#2965, incl. the
typed-response/schema hardening and the drop of Python 3.10):

- controller/node.py: keep upstream's _transitioning/_confirm_status
  lifecycle guard; the kernel-anchor link wiring (node_started) runs
  after the transition completes.
- controller/link.py: keep upstream's add_node rollback (release_ports
  on create failure) and delete via release_ports; release_ports now
  resolves ports live (same staleness reason as _bind_members) and
  discards the node link unconditionally.
- schemas/controller/links.py: extend LinkFilterType with the eight
  kernel-datapath filter types and LinkFilterParameter.type with "str"
  so the newly typed /available_filters response validates; Link.filters
  stays a free-form dict — the vocabulary is capability-gated per link
  and validated by the controller (409), not by a strict request schema.
- schemas/controller/topology.py: drop the type: ignore made redundant
  by the dict filters field.
- tests: route-level filter validation now expects the controller's 409
  (unknown types, out-of-range values); packet_loss correlation is a
  valid kernel parameter (positive test added); OpenAPI assertions match
  the free-form filters property.

gns3server/schemas/controller/topology.py

@@ -32,6 +32,11 @@ from .nodes import Node
 from .projects import Supplier, Variable
 
 
+class TopologyLink(Link):
+    # Legacy topology files store filters as untyped dicts
+    filters: Optional[dict] = None
+
+
 class TopologyType(str, Enum):
     topology = "topology"
 
@@ -39,7 +44,7 @@ class TopologyType(str, Enum):
 class TopologyContent(BaseModel):
     computes: List[Compute] = Field(..., description="List of computes")
     drawings: List[Drawing] = Field(..., description="List of drawings")
-    links: List[Link] = Field(..., description="List of links")
+    links: List[TopologyLink] = Field(..., description="List of links")
     nodes: List[Node] = Field(..., description="List of nodes")