test(event): cover blank event input fallback

[overtrue]

Summary

This change adds a focused regression test for the event add parsing path when users provide blank --event values such as empty strings or comma-only input.

Problem

The recent event-name normalization work updated parse_event_list, but the fallback branch where filtering removes every provided token was still untested. That left a small gap around a real CLI input shape: users can still pass syntactically present but semantically blank event values.

Root Cause

parse_event_list trims and filters each requested event before deciding whether to apply the default s3:ObjectCreated:* event. The no-input case already had coverage, but the distinct path where inputs are present and collapse to an empty list after trimming did not.

Fix

Add test_parse_event_list_defaults_when_inputs_are_blank in crates/cli/src/commands/event.rs. The test asserts that blank and comma-only values still trigger the same default event fallback as an entirely empty event list.

Validation

• cargo fmt --all --check
• cargo clippy --workspace -- -D warnings
• cargo test --workspace