What's Changed
- Fix crash (SIGSEGV) when a CallCredentials plugin throws — If the PHP credentials callable threw an exception (e.g. Google auth failing to fetch a token with unconfigured/invalid credentials), the process crashed with a stack overflow while formatting the error. Affected real-world flows like `FirestoreClient->set()` without working ADC credentials. PHP now gets a clean catchable exception naming the real failure, e.g. `callback failed: plugin threw GuzzleHttp\Exception\ClientException: ...`.
- Report ext-grpc compat version 1.81.0 — keeps pace with Packagist's `grpc/grpc` 1.81.0 so `version_compare()` checks (google-ads-php) keep passing.
- ext-php-rs 0.15.13 → 0.15.15 and other dependency updates.
- New regression test covering the plugin-throws path.
Full Changelog: v0.2.5...v0.2.6