fix: repair imports lost in the 3.1 rebase and meet the new lint baseline

The rebase onto upstream 3.1 (mypy + ruff I001/F401 waves) left the tree
short of the newly enforced baselines in three ways:

* contextlib / UbridgeError imports dropped as false duplicates during
  conflict resolution left NameErrors in iou_vm and qemu_vm (F821);
  the Dynamips router grabbed the compute-level NIOTAP instead of the
  hypervisor one, breaking TAP anchoring (test failure).
* unused imports (KERNEL_UNSUPPORTED_FILTERS, UbridgeError, List) and
  unsorted blocks left behind where the stack's later commits moved the
  last usage elsewhere — ruff I001/F401/RUF022 now enforce these.
* mypy, now baseline-free: cache dict annotations in tc_probe, the
  locators candidate list, the resolved-params None branch in the MCP
  runner, and validate_bpf_syntax keeps the upstream Dict[str, Any]
  return (the strict Optional[str] was wrong for the "valid" bool entry).

The e2e raw-frame probe resolves its compiler via shutil.which (S607)
and zips with strict= (B905); the remaining subprocess call is S603 by
nature and gets a per-file ignore like other test files.

ruff check/format clean, mypy at upstream parity (no new errors),
full unit suite 2167 passed.

gns3server/compute/docker/docker_kernel_datapath.py

@@ -24,14 +24,13 @@ markers, attach/detach, adapter carrier — lives in
 """
 
 import contextlib
+import logging
 
 from gns3server.compute.kernel_datapath import KernelDatapathMixin
 from gns3server.compute.ubridge.ubridge_error import UbridgeError, UbridgeNamespaceError
-
-from .docker_error import DockerError
 from gns3server.utils.kernel_anchor import anchor_suffix, kernel_anchor_name
 
-import logging
+from .docker_error import DockerError
 
 log = logging.getLogger(__name__)
 

gns3server/compute/docker/docker_vm.py

@@ -33,14 +33,13 @@ import aiohttp
 import psutil
 
 from gns3server.compute.compute_error import ComputeError
-from gns3server.compute.ubridge.ubridge_error import UbridgeError, UbridgeNamespaceError
+from gns3server.compute.ubridge.ubridge_error import UbridgeNamespaceError
 from gns3server.utils import int_to_macaddress, macaddress_to_int
 from gns3server.utils.asyncio import monitor_process, wait_for_file_creation, wait_run_in_executor
 from gns3server.utils.asyncio.raw_command_server import AsyncioRawCommandServer
 from gns3server.utils.asyncio.ssh_server import AsyncioSSHServer
 from gns3server.utils.asyncio.telnet_server import AsyncioTelnetServer
 from gns3server.utils.hostname import is_rfc1123_hostname_valid
-from gns3server.utils.packet_filter_validation import KERNEL_UNSUPPORTED_FILTERS
 
 from ..adapters.ethernet_adapter import EthernetAdapter
 from ..base_node import BaseNode

gns3server/compute/docker/iol_docker_vm.py

@@ -672,4 +672,3 @@ class IOLDockerVM(VendorDockerVM):
 
         if self._kernel_host_ifc(adapter_number, port_number) is not None:
             await KernelDatapathMixin._set_adapter_carrier(self, adapter_number, connected, port_number)
-

gns3server/compute/dynamips/nodes/router.py

@@ -42,10 +42,10 @@ from ...base_node import BaseNode
 from ...error import NodeError
 from ...kernel_datapath import KernelDatapathMixin
 from ...nios.nio_bridge import NIOBridge
-from ...nios.nio_tap import NIOTAP
 from ...ubridge.ubridge_error import UbridgeError
 from ..adapters.adapter import ETHERNET_ADAPTERS, ETHERNET_WICS
 from ..dynamips_error import DynamipsError
+from ..nios.nio_tap import NIOTAP
 
 
 class Router(KernelDatapathMixin, BaseNode):

gns3server/compute/iou/iou_vm.py

@@ -22,6 +22,7 @@ order to run an IOU VM.
 import asyncio
 import binascii
 import configparser
+import contextlib
 import functools
 import glob
 import hashlib
@@ -951,9 +952,7 @@ class IOUVM(KernelDatapathMixin, BaseNode):
             raise self._kernel_error(
                 "Bay {bay}/{unit} of IOU '{name}' has no TAP anchor to carry a kernel link "
                 "(serial ports stay on the relay datapath, and a node whose uBridge lacks "
-                "iol_bridge add_nio_tap runs relay-only)".format(
-                    bay=adapter_number, unit=port_number, name=self._name
-                )
+                "iol_bridge add_nio_tap runs relay-only)".format(bay=adapter_number, unit=port_number, name=self._name)
             )
         await self._ubridge_send(
             'iol_bridge add_nio_tap {name} {iol_id} {bay} {unit} "{tap}"'.format(

gns3server/compute/kernel_datapath.py

@@ -41,17 +41,16 @@ A node type using this mixin provides:
   failures surface as ``DockerError`` / ``QemuError`` rather than ``NodeError``.
 """
 
-import os
 import contextlib
+import logging
+import os
 
-from gns3server.utils.tc_capabilities import FILTER_EBPF_MODES, parse_tc_capabilities, usable_ebpf_modes
-from gns3server.compute.ubridge.ubridge_error import UbridgeError
 from gns3server.compute.error import NodeError
+from gns3server.compute.ubridge.ubridge_error import UbridgeError
+from gns3server.utils.tc_capabilities import FILTER_EBPF_MODES, parse_tc_capabilities, usable_ebpf_modes
 
 from .nios.nio_bridge import NIOBridge
 
-import logging
-
 log = logging.getLogger(__name__)
 
 

gns3server/compute/qemu/qemu_vm.py

@@ -20,6 +20,7 @@ order to run a QEMU VM.
 """
 
 import asyncio
+import contextlib
 import json
 import logging
 import math
@@ -53,6 +54,7 @@ from ..kernel_datapath import KernelDatapathMixin
 from ..nios.nio_bridge import NIOBridge
 from ..nios.nio_tap import NIOTAP
 from ..nios.nio_udp import NIOUDP
+from ..ubridge.ubridge_error import UbridgeError
 from .qemu_error import QemuError
 from .utils.qcow2 import Qcow2, Qcow2Error
 from .utils.ziputils import pack_zip, unpack_zip

gns3server/compute/ubridge/tc_probe.py

@@ -32,29 +32,31 @@ failure (missing binary, old build answering "Unknown command", timeout)
 means unknown, reported as None and cached as such.
 """
 
-import os
-import uuid
-import shutil
 import asyncio
-import tempfile
-import logging
 import contextlib
+import logging
+import os
+import shutil
+import tempfile
+import uuid
+from typing import Optional
 
 from gns3server.config import Config
 from gns3server.utils.tc_capabilities import parse_tc_capabilities
+
 from .hypervisor import Hypervisor
 from .ubridge_error import UbridgeError
 
 log = logging.getLogger(__name__)
 
 # binary identity -> parsed report (None = probed and unusable)
-_cache = {}
+_cache: dict[tuple[str, int, int], Optional[dict[str, str]]] = {}
 # binary identity -> whether the tap module works (None = unknown)
-_tap_cache = {}
+_tap_cache: dict[tuple[str, int, int], Optional[bool]] = {}
 # binary identity -> whether iol_bridge can bind a port to a TAP (None = unknown)
-_iol_tap_cache = {}
+_iol_tap_cache: dict[tuple[str, int, int], Optional[bool]] = {}
 # binary identity -> whether the bridge module can release a named TAP NIO (None = unknown)
-_bridge_tap_cache = {}
+_bridge_tap_cache: dict[tuple[str, int, int], Optional[bool]] = {}
 _lock = asyncio.Lock()
 
 
@@ -252,9 +254,7 @@ async def _probe_iol_tap(path, config, timeout):
             await hypervisor.send(f"iol_bridge create {bridge} {_IOL_PROBE_BRIDGE_ID}")
             try:
                 await hypervisor.send(f"tap create {tap}")
-                await hypervisor.send(
-                    f"iol_bridge add_nio_tap {bridge} {_IOL_PROBE_BRIDGE_ID - 1} 0 0 {tap}"
-                )
+                await hypervisor.send(f"iol_bridge add_nio_tap {bridge} {_IOL_PROBE_BRIDGE_ID - 1} 0 0 {tap}")
                 await hypervisor.send(f"iol_bridge delete_nio_tap {bridge} 0 0")
             finally:
                 # iol_bridge delete releases every port NIO (the TAP fd),