chore: archive generic-network-robotics-framework; sync 9 delta specs

- Archived to openspec/changes/archive/2026-06-01-generic-network-robotics-framework/
- Synced 9 delta specs to openspec/specs/:
  eval-tool-interface, experiment-leaderboard, gazebo-ros-auto-launch,
  mininet-docker-integration, parameter-sweep, plugin-orchestrator,
  scenario-runner, task-folder-convention, unified-config-schema

Author: srikrishna3118