Fix PHP 8 deprecations in v5

Merge the verified PHP 8 deprecation fixes into v5.

Add PSR-7 v2 compatibility

Support React Promise 3 error responses

Restler 5.0.15

Constraint: v5 users needed the recently merged Swagger proxy and PHP warning fixes without waiting for a v6 migration.

Rejected: Mutating 5.0.14 again | the new PR merges and hardening commit deserve a new patch release.

Confidence: high
Scope-risk: narrow
Directive: Keep v5 releases on the 5.0.x line and preserve contributor PR merge commits.
Tested: php -l src/Resources.php; php -l src/Filter/RateLimit.php; composer validate --strict --no-check-publish; forwarded-proto rewrite probe
Not-tested: Full Behat after 02c5f2f; prior combined branch run had 281 passed and 4 stateful fixture failures.

Restler 5.0.14

Constraint: v5 needed a patch release after restoring missing 5.0.10-5.0.13 history, merging PHP 8.5 compatibility fixes, and excluding generated Composer vendor packages.

Rejected: Leaving the release tag before the vendor ignore hygiene commit | the v5 release should reflect the branch state users install from.

Confidence: high

Scope-risk: moderate

Directive: Keep v5 releases on the 5.0.x line; do not move existing 5.0.10-5.0.13 tags.

Tested: composer validate --strict --no-check-publish; php -l changed PHP files; full Behat suite 285 scenarios / 1530 steps; git check-ignore -v vendor/nikic/php-parser/composer.json

Not-tested: PHP versions below 8.5 in this release pass

Restler 6.0.1

Security dependency refresh for Dependabot-reported advisories.

Restler v6.0.0 - Modern PHP 8+ with async support and full documentation

Fixes dynamic property creation error in PHP 8.3

Fixes unwanted dependency by avoiding dependencies check too early

FIxes object handling for nesting by dot