Core services and framework integration

Daycry\Twig\Twig owns rendering context and coordinates independent services:

Service	Responsibility
Configuration / Configuration\TwigOptions	Explicit framework-independent settings
Discovery\TemplateDiscovery	Enumerate loader paths, track request-local hits, validate snapshots
Cache\TemplateCacheManager	Track logical compile state; it is not proof that a cache artifact exists
Warmup\TemplateWarmer	Compile source, check artifact freshness and preserve source fingerprints
Invalidation\TemplateInvalidator	Remove artifacts through native Twig keys and refresh loaded templates
Persistence\StateRepository	Read/write metadata through JSON files or Contracts\CacheStoreInterface
Registry\DynamicRegistry	Retain dynamic functions and filters across environment resets
Logging\TwigLogger	Optional injected PSR-3 logging
Profile\RenderProfiler	Bounded per-template timing aggregation

Configuration is resolved before the cache manager, warmer and invalidator are wired. They share one manager. Persistent loading is scoped to each renderer; a previous instance cannot suppress initialization in another instance.

To supply metadata storage, implement CacheStoreInterface and pass it as the third renderer constructor argument. A custom compiled Twig cache is configured separately through Configuration::$compiledCache. A remote compiled cache must implement Twig's removable cache interface for targeted invalidation. Implement ClearableCacheInterface when it also supports clearing its entire namespace. Implement RefreshableCacheInterface for distributed invalidation: the renderer refreshes it once per render/warmup operation and rebuilds loaded templates if it changed.

The optional adapter is in packages/codeigniter4/src, under Daycry\Twig\CodeIgniter4. Its configuration converts to the core configuration; its renderer subclasses the core to install helpers, logger, event notification, cache-service storage and debug toolbar behavior. Services, Spark commands, configuration publishing and the Viewable trait belong to this adapter only.

The architecture check forbids dependencies from src/ on framework or adapter classes. Consumer checks also install and execute the core without CodeIgniter.

Runtime\Environment adds an isolated class revision after an explicit reset. PHP classes cannot be unloaded; the revision prevents loaded templates and their includes from retaining old source. Normal fresh instances use stable Twig keys. Globals and dynamic registrations are reapplied when the environment is rebuilt.

Cache\FilesystemCache shares generation changes through a fixed marker and Support\AtomicFileWriter performs atomic metadata replacement. Warmup compiles shared persistent class identities separately from runtime reset revisions. resetDiagnostics() is the common backend-aware maintenance API used by Spark.