[ci] chore: migrate all rm related ci to reward loop

[yyDing1]

What does this PR do?

• Migrate all Reward-Model-related CI to Reward Loop (verified)
• Set the naive router as the default for the reward loop

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[gemini-code-assist]

Code Review

This pull request migrates all Reward-Model-related CI to use the new reward_loop feature. The changes span across example scripts, test scripts, and configuration files, consistently replacing the old reward model setup with the reward_loop configuration. The core logic in verl/trainer/ppo/ray_trainer.py is updated to handle both the legacy and the new reward_loop paths. I've found one minor issue in a test script where a parameter is duplicated. Overall, the changes look good and align with the PR's objective.

[gemini-code-assist]

The parameter reward_model.use_reward_loop=True is duplicated. Please remove this redundant line to improve clarity and avoid potential issues.