chore(lint): apply the 3.1 f-string wave to the kernel-datapath code

The rebase onto 65c858d45 brought upstream's UP032 enforcement; the
conflict resolution kept this branch's semantics on the overlapping
lines, so their .format() calls needed the conversion afterwards
(ruff check --fix, 41 sites) plus the formatter's rewrap (7 files).

Replicates the CI recipe locally: pip check, ruff check/format, mypy
2.3.1 (clean, 434 files), unit suite 2216 passed.

gns3server/compute/base_node.py

@@ -1226,7 +1226,7 @@ class BaseNode:
 
         # mark <bpf> [tag <id>] [pcap <path>] — tag/pcap keyword pairs, any order.
         self._validate_marker_name(name)
-        cmd = 'bridge add_packet_filter {bridge} {name} mark "{bpf}"'.format(bridge=bridge_name, name=name, bpf=bpf)
+        cmd = f'bridge add_packet_filter {bridge_name} {name} mark "{bpf}"'
         if tag is not None:
             cmd += f" tag {tag}"
         # Per-link attribution (contract §3.2): when one ubridge bridge serves