refactor(marker): converge to filter single-path model, remove dual-apply endpoints

Markers now follow exactly the same apply pattern as packet filters:
state lives in Link._markers, application goes through NIO
(update() -> PUT /nio -> _ubridge_apply_markers). The former
immediate-apply REST endpoints (/markers/start, /markers/stop on
the compute side) and the per-node start_marker/stop_marker methods
are removed — they were a legacy of the original capture-inspired
design and have been superseded by the NIO flow.

Changes:
- controller/udp_link: start_marker/stop_marker/update_marker now
  set _markers state + call self.update() (mirrors update_filters).
  Removed _marker_capture_nodes runtime dict and its helpers.
- controller/project: _create_link_from_topology_data restores
  _markers directly from persisted data (with BPF validation,
  like filter reload). No long calls start_marker during load.
- compute: _ubridge_apply_markers swallows BPF compile errors
  (warn+skip), matching _ubridge_apply_filters behaviour so a
  single bad expression cannot break link creation / node restart.
- Removed: /markers/start,stop endpoints (6 handlers across
  vpcs/qemu/docker route files), node start_marker/stop_marker
  methods (3 VM files), _ubridge_delete_marker_filter,
  _marker_capture_nodes, MarkerDelete schema.

Net: ~280 lines of dead code removed; marker and packet filter now
share a single, unified apply path via the NIO.

gns3server/api/routes/compute/docker_nodes.py

@@ -29,8 +29,6 @@ from typing import Union
 from gns3server import schemas
 from gns3server.compute.docker import Docker
 from gns3server.compute.docker.docker_vm import DockerVM
-from gns3server.compute.marker.marker_manager import MarkerManager
-
 from .dependencies.authentication import compute_authentication, ws_compute_authentication
 
 responses = {404: {"model": schemas.ErrorMessage, "description": "Could not find project or Docker node"}}
@@ -355,60 +353,6 @@ async def stop_docker_node_capture(
     await node.stop_capture(adapter_number)
 
 
-@router.post(
-    "/{node_id}/adapters/{adapter_number}/ports/{port_number}/markers/start",
-    dependencies=[Depends(compute_authentication)]
-)
-async def start_docker_node_marker(
-    *,
-    project_id: UUID,
-    adapter_number: int,
-    port_number: int,
-    marker_data: schemas.MarkerCreate,
-    node: DockerVM = Depends(dep_node)
-) -> dict:
-    """
-    Attach a traffic-insight ``mark`` filter to the Docker node's uBridge bridge.
-    """
-
-    pcap_path = os.path.join(
-        node.project.markers_working_directory(),
-        f"{node.id}_{marker_data.link_id}_{marker_data.name}.pcap"
-    )
-    await node.start_marker(adapter_number, marker_data.name, marker_data.bpf, pcap_path, marker_data.tag)
-    MarkerManager.instance().register(
-        str(project_id), node.id, marker_data.name, marker_data.link_id, marker_data.tag
-    )
-    nio = node.get_nio(adapter_number)
-    if nio:
-        nio.markers[marker_data.name] = {
-            "bpf": marker_data.bpf, "tag": marker_data.tag, "link_id": marker_data.link_id
-        }
-    return {"pcap_file_path": str(pcap_path)}
-
-
-@router.post(
-    "/{node_id}/adapters/{adapter_number}/ports/{port_number}/markers/stop",
-    status_code=status.HTTP_204_NO_CONTENT,
-    dependencies=[Depends(compute_authentication)]
-)
-async def stop_docker_node_marker(
-    adapter_number: int,
-    port_number: int,
-    marker_data: schemas.MarkerDelete,
-    node: DockerVM = Depends(dep_node)
-) -> None:
-    """
-    Remove a traffic-insight ``mark`` filter from the Docker node's uBridge bridge.
-    """
-
-    await node.stop_marker(adapter_number, marker_data.name)
-    MarkerManager.instance().unregister(node.id, marker_data.name)
-    nio = node.get_nio(adapter_number)
-    if nio:
-        nio.markers.pop(marker_data.name, None)
-
-
 @router.get(
     "/{node_id}/adapters/{adapter_number}/ports/{port_number}/capture/stream",
     dependencies=[Depends(compute_authentication)]

gns3server/api/routes/compute/qemu_nodes.py

@@ -30,8 +30,6 @@ from gns3server import schemas
 from gns3server.compute import qemu
 from gns3server.compute.qemu import Qemu
 from gns3server.compute.qemu.qemu_vm import QemuVM
-from gns3server.compute.marker.marker_manager import MarkerManager
-
 from .dependencies.authentication import compute_authentication, ws_compute_authentication
 
 import logging
@@ -384,60 +382,6 @@ async def stop_qemu_node_capture(
     await node.stop_capture(adapter_number)
 
 
-@router.post(
-    "/{node_id}/adapters/{adapter_number}/ports/{port_number}/markers/start",
-    dependencies=[Depends(compute_authentication)]
-)
-async def start_qemu_node_marker(
-    *,
-    project_id: UUID,
-    adapter_number: int,
-    marker_data: schemas.MarkerCreate,
-    port_number: int = Path(..., ge=0, le=0),
-    node: QemuVM = Depends(dep_node)
-) -> dict:
-    """
-    Attach a traffic-insight ``mark`` filter to the QEMU node's uBridge bridge.
-    """
-
-    pcap_path = os.path.join(
-        node.project.markers_working_directory(),
-        f"{node.id}_{marker_data.link_id}_{marker_data.name}.pcap"
-    )
-    await node.start_marker(adapter_number, marker_data.name, marker_data.bpf, pcap_path, marker_data.tag)
-    MarkerManager.instance().register(
-        str(project_id), node.id, marker_data.name, marker_data.link_id, marker_data.tag
-    )
-    nio = node.get_nio(adapter_number)
-    if nio:
-        nio.markers[marker_data.name] = {
-            "bpf": marker_data.bpf, "tag": marker_data.tag, "link_id": marker_data.link_id
-        }
-    return {"pcap_file_path": str(pcap_path)}
-
-
-@router.post(
-    "/{node_id}/adapters/{adapter_number}/ports/{port_number}/markers/stop",
-    status_code=status.HTTP_204_NO_CONTENT,
-    dependencies=[Depends(compute_authentication)]
-)
-async def stop_qemu_node_marker(
-    adapter_number: int,
-    marker_data: schemas.MarkerDelete,
-    port_number: int = Path(..., ge=0, le=0),
-    node: QemuVM = Depends(dep_node)
-) -> None:
-    """
-    Remove a traffic-insight ``mark`` filter from the QEMU node's uBridge bridge.
-    """
-
-    await node.stop_marker(adapter_number, marker_data.name)
-    MarkerManager.instance().unregister(node.id, marker_data.name)
-    nio = node.get_nio(adapter_number)
-    if nio:
-        nio.markers.pop(marker_data.name, None)
-
-
 @router.get(
     "/{node_id}/adapters/{adapter_number}/ports/{port_number}/capture/stream",
     dependencies=[Depends(compute_authentication)]

gns3server/api/routes/compute/vpcs_nodes.py

@@ -29,8 +29,6 @@ from uuid import UUID
 from gns3server import schemas
 from gns3server.compute.vpcs import VPCS
 from gns3server.compute.vpcs.vpcs_vm import VPCSVM
-from gns3server.compute.marker.marker_manager import MarkerManager
-
 from .dependencies.authentication import compute_authentication, ws_compute_authentication
 
 responses = {404: {"model": schemas.ErrorMessage, "description": "Could not find project or VMware node"}}
@@ -305,65 +303,6 @@ async def stop_vpcs_node_capture(
     await node.stop_capture(port_number)
 
 
-@router.post(
-    "/{node_id}/adapters/{adapter_number}/ports/{port_number}/markers/start",
-    dependencies=[Depends(compute_authentication)]
-)
-async def start_vpcs_node_marker(
-    *,
-    project_id: UUID,
-    port_number: int,
-    marker_data: schemas.MarkerCreate,
-    adapter_number: int = Path(..., ge=0, le=0),
-    node: VPCSVM = Depends(dep_node)
-) -> dict:
-    """
-    Attach a traffic-insight ``mark`` filter to the VPCS node's uBridge bridge.
-    On BPF match uBridge emits a MARK signal and appends the packet to the pcap.
-    """
-
-    pcap_path = os.path.join(
-        node.project.markers_working_directory(),
-        f"{node.id}_{marker_data.link_id}_{marker_data.name}.pcap"
-    )
-    await node.start_marker(port_number, marker_data.name, marker_data.bpf, pcap_path, marker_data.tag)
-    MarkerManager.instance().register(
-        str(project_id), node.id, marker_data.name, marker_data.link_id, marker_data.tag
-    )
-    # Mirror the marker spec onto the NIO so it survives a node restart (the NIO
-    # persists across stop/start and _ubridge_apply_markers re-applies its markers).
-    nio = node.get_nio(port_number)
-    if nio:
-        nio.markers[marker_data.name] = {
-            "bpf": marker_data.bpf,
-            "tag": marker_data.tag,
-            "link_id": marker_data.link_id,
-        }
-    return {"pcap_file_path": pcap_path}
-
-
-@router.post(
-    "/{node_id}/adapters/{adapter_number}/ports/{port_number}/markers/stop",
-    status_code=status.HTTP_204_NO_CONTENT,
-    dependencies=[Depends(compute_authentication)]
-)
-async def stop_vpcs_node_marker(
-    *,
-    port_number: int,
-    marker_data: schemas.MarkerDelete,
-    adapter_number: int = Path(..., ge=0, le=0),
-    node: VPCSVM = Depends(dep_node)
-) -> None:
-    """
-    Remove a traffic-insight ``mark`` filter from the VPCS node's uBridge bridge.
-    """
-
-    await node.stop_marker(port_number, marker_data.name)
-    MarkerManager.instance().unregister(node.id, marker_data.name)
-    nio = node.get_nio(port_number)
-    if nio:
-        nio.markers.pop(marker_data.name, None)
-
 
 @router.get(
     "/{node_id}/adapters/{adapter_number}/ports/{port_number}/capture/stream",