Add cache_calls metric for persistent object cache integration

[Copilot]

Multiple persistent object cache plugins expose backend call counts, but wp profile had no way to surface this data.

Changes

• src/Logger.php — adds $cache_calls public property; adds get_object_cache_calls() static helper that reads from whichever backend is active; start() captures the offset, stop() computes and stores the delta. Gracefully no-ops (shows 0) when no supported backend is present.
• src/Profiler.php — adds $tick_cache_calls_offset for tick-based (function-level) profiling; mirrors the same offset/delta pattern in handle_function_tick() via the shared helper.
• src/Command.php — adds cache_calls to the $metrics fields for stage, hook, eval, and eval-file subcommands.
• features/profile-eval.feature — two new scenarios: one asserting cache_calls = 0 with the default cache; one using a minimal object-cache.php drop-in that mimics the cache_calls array format to assert the count is correct.

Supported backends

The get_object_cache_calls() helper checks each source in order:

Plugin	Property / Method
WP Redis	$wp_object_cache->redis_calls (array of command → count)
Redis Object Cache	$wp_object_cache->cache_calls (array of command → count)
Object Cache Pro	$wp_object_cache->metrics()->storeReads + storeWrites

Example output

$ wp profile eval 'wp_cache_set( "foo", "bar" ); wp_cache_get( "foo" ); wp_cache_get( "foo" );' \
    --fields=cache_hits,cache_misses,cache_calls
+------------+--------------+-------------+
| cache_hits | cache_misses | cache_calls |
+------------+--------------+-------------+
| 2          | 0            | 3           |
+------------+--------------+-------------+

[codecov]

Codecov Report

❌ Patch coverage is 58.13953% with 18 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/Profiler.php	0.00%	14 Missing ⚠️
src/Logger.php	84.00%	4 Missing ⚠️

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[Copilot]

Pull request overview

Adds a new cache_calls metric to wp profile output to surface persistent object cache backend call counts across supported implementations (WP Redis, Redis Object Cache, Object Cache Pro), including end-to-end Behat coverage.

Changes:

• Add Logger::get_object_cache_calls() helper and track cache_calls delta in Logger::start()/stop().
• Extend tick-based profiling to accumulate cache_calls per function in Profiler::handle_function_tick().
• Expose cache_calls as a selectable field for stage, hook, eval, and eval-file, and add Behat scenarios covering supported/unsupported backends.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/Logger.php	Introduces cache_calls metric storage and backend-specific call counting helper.
src/Profiler.php	Tracks cache_calls deltas during tick-based (function-level) profiling.
src/Command.php	Adds cache_calls to field lists for relevant subcommands.
features/profile-eval.feature	Adds Behat scenarios validating cache_calls behavior with/without a persistent cache backend.

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