Speed up native URL rewriting

[adamziel]

What

• Route URLInTextProcessor through NativeURLInTextProcessor when the native extension is loaded, while preserving the public PHP API around parsing, validation, and replacement.
• Add a bounded ring cache for parsed native URL candidates.
• Add a bounded ring cache in wp_rewrite_urls() for final rewrite decisions keyed by mapping, token type, and raw URL.
• Update the native extension README to describe the wrapper-based URL native default.

Why

Large imports can contain hundreds of thousands of repeated URL occurrences. The native scanner can find candidates quickly, but the old public path still paid repeated PHP WHATWG parsing and replace_base_url() costs for the same raw URLs.

The caches are capped at 4096 entries each to avoid unbounded memory growth.

Benchmarks

Fixture: 5,000 sampled post_content values from a large Studio/reprint dump, 16.9 MB decoded content, 350,000 URL occurrences, 2 unique raw URLs. Runtime: PHP.wasm 8.4.21 with wp_native_apis loaded.

Measure	Before	After	Delta
wp_rewrite_urls() wall time	90.18s	3.57s	-86.60s (-96.0%)
Output hash	44c9750c...	44c9750c...	identical
Public URL processor parent	PHPURLInTextProcessor	NativeURLInTextProcessorWrapper	native scanner active

Validation

• vendor/bin/phpcbf -d memory_limit=1G components/DataLiberation/URL/class-nativeurlintextprocessorwrapper.php components/DataLiberation/URL/class-urlintextprocessor.php components/DataLiberation/URL/functions.php
• vendor/bin/phpcs -d memory_limit=1G components/DataLiberation/URL/class-nativeurlintextprocessorwrapper.php components/DataLiberation/URL/class-urlintextprocessor.php components/DataLiberation/URL/functions.php
• vendor/bin/phpunit -c phpunit.xml components/DataLiberation/Tests/URLInTextProcessorTest.php components/DataLiberation/Tests/RewriteUrlsTest.php
• php extensions/native-apis/tests/verify-native-apis.php --allow-missing
• native-wrapper smoke test with a fake native scanner
• WASM benchmark with wp_native_apis loaded

Full composer test currently has one unrelated failure in WordPress\\Blueprints\\Tests\\Unit\\Steps\\DefineConstantsStepTest::testAddNewConstantsToInvalidWpConfig on PHP 8.4.5: the expected Blueprint error text is absent from the subprocess exception output.