perf: batch update/delete marker-def fan-out too (full project-level)

per-def operations are project-level — create, update AND delete all
modify the marker policy on every link — so all three must batch, not
just create.

Extend memory_only to update_marker and stop_marker (merge/delete into
_markers + refresh _link_data, no per-link HTTP), and route
update_marker_definition and delete_marker_definition through the same
two-phase path as create: memory-only per link, then one
PUT /projects/{id}/nios/batch per compute.

Trade-off: a full reapply resets every marker's pcap on the link (the
old precise update_marker/stop_marker preserved sibling pcaps). For
project-level policy changes this is acceptable — real-time insight
matters more than pcap continuity, and batching turns 5000+ round-trips
into one per compute.

.gitignore

@@ -86,3 +86,4 @@ venv
 gns3server/agent/gns3_copilot/cache/tiktoken/
 
 gns3.log
+/configs/