Refine HttpClient factory lifecycle and request helper API after #534 #563

Follow-up to #534. The adapter extraction introduced CurlAdapter and MultiCurlAdapter, but the public creation/lifecycle model is still unclear.

Current issues:

• HttpClientFactory::get() returns a cached mutable HttpClient.
• HttpClient stores request-specific state: method, data, request headers, responses, and errors.
• Reusing a cached HttpClient can leak state between requests unless every create*Request() call resets state.
• HttpClientType exists but is not currently used.
• HttpClient directly constructs CurlAdapter / MultiCurlAdapter.
• Public usage is unclear: new HttpClient(), HttpClientFactory::get(), and future helper usage are not aligned.
• Core packages currently instantiate or inject HttpClient directly and call createRequest(), so removing those methods immediately is not safe.

Goal

Define and implement a coherent request-context creation model for HttpClient, while preserving backward compatibility with existing consumers.

Proposed Direction

Treat HTTP requests as fresh request contexts, closer to PaginatorFactory::create(...) than cached service factories like Cache/Mailer.

Add factory methods that return fresh configured clients:

HttpClientFactory::createRequest(string $url, ?Curl $client = null): HttpClient
HttpClientFactory::createMultiRequest(?MultiCurl $client = null): HttpClient
HttpClientFactory::createAsyncMultiRequest(callable $success, callable $error, ?MultiCurl $client = null): HttpClient

Add helper functions:

httpRequest(string $url, ?Curl $client = null): HttpClient
httpMultiRequest(?MultiCurl $client = null): HttpClient
httpAsyncMultiRequest(callable $success, callable $error, ?MultiCurl $client = null): HttpClient

Keep existing instance methods for compatibility:

HttpClient::createRequest()
HttpClient::createMultiRequest()
HttpClient::createAsyncMultiRequest()

Do not promote cached HttpClientFactory::get() for request usage. Either remove it if safe, or deprecate it if it may already be used externally.

Tasks

1. Audit current core usages of HttpClient.
2. Add fresh request-context factory methods.
3. Add helper functions for single, multi, and async multi requests.
4. Decide whether HttpClientFactory::get() should be removed or deprecated.
5. Decide whether HttpClientType should be removed or used internally.
6. Keep backward-compatible HttpClient::create*Request() methods unless a breaking change is explicitly accepted.
7. Add tests proving each factory/helper call returns a fresh request context.
8. Add tests for no stale state between sequential requests.
9. Update core package usages where appropriate:
   • Captcha
   • Lang
   • Storage
   • Mailer
10. Update documentation/changelog with recommended usage.

Acceptance Criteria

• httpRequest($url) creates a fresh single-request HttpClient.
• httpMultiRequest() creates a fresh multi-request HttpClient.
• httpAsyncMultiRequest($success, $error) creates a fresh async multi-request HttpClient.
• Factory request-creation methods return fresh instances.
• No request state leaks between factory/helper-created requests.
• Existing direct usage with new HttpClient()->createRequest() still works.
• Existing core package tests pass.
• Downstream save_remote_image() works using the new helper/factory style.
• HttpClientType is either used meaningfully or removed.
• HttpClientFactory::get() is removed or clearly deprecated to avoid cached mutable-request misuse.

Validation

Run:

vendor/bin/phpunit tests/Unit/HttpClient
vendor/bin/phpunit tests/Unit/Captcha tests/Unit/Lang tests/Unit/Storage tests/Unit/Mailer
composer cs:check
composer phpstan

Also perform downstream smoke test in quantum-php-project:

• point quantum/framework to local core path repository;
• update save_remote_image() to use the new helper/factory style;
• verify a real HTTP image download saves the expected file body.