1.16.0

Fixed

• File caches degrade gracefully in read-only environments (e.g. a read-only project root inside a build sandbox) instead of fataling the bootstrap with Directory "..." was not created: the class-resolver caches fall back to in-memory resolution, the merged-config auto-warm becomes a no-op, and cache writes never throw or emit raw PHP warnings. Pre-warmed cache files inside a read-only directory remain readable, so warm-at-build/run-read-only deployments keep their cache hits.

Added

• WritableDirectory::isUsable() answers whether a directory can hold cache files (creating it when missing), memoized per directory
• FileCache::isPersistent() reports whether entries reach disk or only live in memory; FileCache::writeAtomically() returns whether the file was written

Full changelog: 1.15.0...1.16.0