* Increase default EC2 client QPS and node worker count to reduce trunk… (#675)

* Increase default EC2 client QPS and node worker count to reduce trunk ENI init latency

Scale testing showed 4-5x improvement in trunk ENI initialization time
at 1000-node scale by increasing these defaults. The new values (24 QPS,
36 burst, 20 workers) stay well within default EC2 API throttling limits
(mutating APIs refill at 5/sec with bucket max 50) and require no
customer action or EC2 quota increases.

Previous defaults: --user-client-qps=12, --user-client-burst=18, --node-mgr-workers=10
New defaults:      --user-client-qps=24, --user-client-burst=36, --node-mgr-workers=20

* Bump golang.org/x/net to v0.55.0 to fix GO-2026-5026

Fixes govulncheck failure caused by a Punycode label validation
vulnerability in golang.org/x/net/idna (v0.54.0).

* Updating limits.go (#677)