Add --plugin grouping to wp profile hook resource output

[Copilot]

wp profile could not report resource usage at plugin granularity when profiling hooks. This change adds a plugin-level view so callback metrics can be aggregated per plugin via a first-class CLI flag.

• Hook command surface

  • Added --plugin to wp profile hook options.
  • Updated command synopsis/docs (README.md, feature usage output) to include the new flag.

• Plugin-level aggregation

  • Added grouping path in Command::hook() to aggregate callback metrics by plugin when --plugin is set.
  • Aggregates time, query/cache/request counters and durations, and computes aggregate cache_ratio.
  • Supports both standard plugins and mu-plugins by deriving plugin slug from callback location.

• Behavior constraints

  • --plugin is only valid when profiling callbacks (wp profile hook <hook> or --all).
  • Returns a clear error if used on hook summary mode.

• Acceptance coverage

  • Added Behat scenario validating plugin-grouped output for a test plugin on init.

wp profile hook init --plugin --fields=plugin,cache_hits,cache_misses

Example output shape:

+---------------+------------+--------------+
| plugin        | cache_hits | cache_misses |
+---------------+------------+--------------+
| resource-test | 0          | 1            |
+---------------+------------+--------------+
| total (1)     | 0          | 1            |
+---------------+------------+--------------+

[swissspidy]

@copilot to make this work, you need to install wp-cli/extension-command as a composer development dependency.

[Copilot]

Implemented in 9aa3a6d: added wp-cli/extension-command to require-dev in composer.json so Behat scenarios can use wp plugin ... commands.