test(cli): cover top-level event parser aliases

[overtrue]

Summary

This adds focused parser coverage for the deprecated top-level rc event entrypoints that were rewired through EventArgs in the recent command-surface updates.

The current parser tests cover nested rc bucket event ... forms and one top-level rc event list ... compatibility path, but they do not assert that the top-level add and remove flows still deserialize correctly. That leaves a regression gap around the exact deprecated aliases users may still invoke after the Commands::Event(event::EventArgs) wiring change.

Root cause

Coverage stopped at the list alias. The parser test suite did not exercise the more argument-heavy top-level event add and event remove branches, so a clap wiring regression there could go unnoticed while adjacent tests still passed.

Fix

Add two parser tests in crates/cli/src/commands/mod.rs that verify:

• rc event add <path> <arn> --event put,delete --force
• rc event remove <path> <arn> --force

Both assertions confirm the top-level deprecated entrypoint still resolves through EventArgs, preserves the expected positional arguments, and forwards the --force and --event flags.

Validation

I ran these successfully:

• cargo test -p rustfs-cli cli_accepts_top_level_event_ --lib
• cargo fmt --all --check
• cargo clippy --workspace -- -D warnings
• cargo test --workspace

I also attempted make pre-commit because the automation requires it, but origin/main does not define a pre-commit target, so make exits with No rule to make target 'pre-commit'.