Rename cacheKey option to key

[ChiragAgg5k]

What

Renames the shared-state constructor option from cacheKey to key.

This updates:

• CircuitBreaker::__construct() named argument and internal property
• cache field namespacing and telemetry circuit_breaker.name source
• unit and e2e test usage
• README examples and configuration list
• telemetry demo request/config field names

Why

key is shorter and matches the cache PR usage while still describing the circuit breaker state namespace.

Testing

• composer format
• composer lint
• composer test:unit
• php -d memory_limit=512M vendor/bin/phpstan analyse

Note: plain composer check hit the local default 128 MB PHP memory limit, so PHPStan was rerun directly with memory_limit=512M.

[greptile-apps]

Greptile Summary

This PR performs a mechanical rename of the cacheKey constructor parameter and internal property to key across the entire codebase, with no functional changes to circuit breaker behaviour.

• CircuitBreaker::__construct() named argument, private property, cache field namespacing, and telemetry circuit_breaker.name attribute are all updated consistently.
• All tests (unit and e2e), README examples, and telemetry demo files (PHP, HTML, JS) are updated in lockstep; the helper function cacheKey() in server.php is also opportunistically renamed to normalizeKey() for clarity.

Confidence Score: 5/5

Pure rename with no logic changes — safe to merge.

Every call site, test, doc example, and template that referenced cacheKey has been updated to key. The rename is complete and internally consistent across all nine changed files, with the existing test suite providing good coverage of the renamed parameter.

No files require special attention.

Important Files Changed

Filename	Overview
src/CircuitBreaker/CircuitBreaker.php	Renames private property $cacheKey to $key and updates all internal usages including cache field namespacing and telemetry attribute
examples/telemetry/server.php	Renames array key and local variable from cacheKey to key; also renames helper function cacheKey() to normalizeKey() for clarity. Env var BREAKER_DEMO_CACHE_KEY intentionally left as-is for backward compatibility.
examples/telemetry/public/app.js	Updates DOM element references and payload field from cacheKey/activeCacheKey to key/activeKey consistently
examples/telemetry/public/index.html	Renames HTML element IDs activeCacheKey and cacheKey to activeKey and key to match updated JS selectors
tests/unit/CircuitBreakerTest.php	Updates all named argument usages from cacheKey: to key: across unit tests
tests/e2e/RedisAdapterTest.php	Updates named argument from cacheKey: to key: in shared-state e2e test
tests/e2e/SwooleTableAdapterTest.php	Updates named argument from cacheKey: to key: in Swoole shared-state e2e test
README.md	Updates all code examples and the constructor option table to use key instead of cacheKey
examples/telemetry/scenario.php	Updates config array key and PHPDoc type annotation from cacheKey to key

_{Reviews (2): Last reviewed commit: "Rename cacheKey option to key" | Re-trigger Greptile}