chore: bump gpu-operator to v26.7.0

[dholt]

Bump gpu-operator v26.3.3 -> v26.7.0

What this is

Bump the gpu-operator version pin. In roles/nvidia-gpu-operator/defaults/main.yml, change gpu_operator_chart_version from v26.3.3 to v26.7.0. The upstream latest value was verified against https://github.com/NVIDIA/gpu-operator/releases when this card was generated; do not attempt network verification (network is disabled). Update any version references to the same component inside the allowed paths only, keep the change minimal, and do not touch unrelated pins. If the file structure does not match this instruction (variable missing, value already changed, format drifted), stop and report GATE_REQUIRED: card is stale, instead of guessing.

Verification

• Deterministic checks passed: diff check, public sanitizer, bump applied, old value gone, parent commit
• Two independent agent reviews approved head 7b1a9a09e1c2 (different model vendors; strict verdict contract)
• Published by the DeepOps maintenance loop's deterministic publisher after its publication gate (reviews, provenance, exact-head) passed