Fix plugin enable verbose output

[OnlyYu1996]

Fixes PlatformNetwork/bounty-challenge#53098.

Summary

• pass the global --verbose flag into plugin command dispatch
• add extra diagnostic output for plugin enable in verbose mode: plugin directory, manifest path, previous enabled state, and current enabled state
• add regression coverage for global verbose parsing and verbose enable output
• update stale agent command test import so current cortex-cli tests build

Validation

• cargo +stable fmt --package cortex-cli --check
• cargo +stable test --package cortex-cli plugin_cmd::tests::test_plugin_enable_verbose_output_adds_diagnostics -- --nocapture
• cargo +stable test --package cortex-cli cli::args::tests::test_cli_global_verbose_with_plugin_enable -- --nocapture
• cargo +stable check --package cortex-cli --lib
• cargo +stable build --package cortex-cli --bin Cortex
• git diff --check

[greptile-apps]

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