v0.5.20260411

A primarily architectural release focused on shared-system hardening, safer runtime ownership, and a major expansion of Sonic 3 & Knuckles gameplay coverage.

• Two-tier service architecture landed across the object system: GameServices and ObjectServices now replace pervasive singleton access, with broad NoOp/null-check cleanup and cleaner per-object service boundaries.
• GameRuntime now owns mutable gameplay state explicitly, backed by resetState() lifecycle support across the singleton-heavy engine. This improves test isolation, teardown safety, and future editor/play-test workflows.
• LevelManager decomposition split one of the engine's largest subsystems into focused components, and MutableLevel landed as the foundation for future in-engine level editing, undo/redo, and dirty-region updates.
• Common code extraction and cross-game hardening removed a large amount of duplication across S1, S2, and S3K, while improving shared abstractions such as cross-game donation, animation translation, sidekick handling, and trace/test infrastructure.
• Knuckles is now playable with ROM-accurate glide/climb behaviour, and cross-game support also improved through broader donation capabilities and multi-sidekick infrastructure.
• Sonic 3 & Knuckles advanced significantly: AIZ now includes miniboss defeat flow, signpost/results, AIZ2 Flying Battery bombing, AIZ2 end boss, post-boss sequence, and the AIZ-to-HCZ transition.
• Hydrocity Zone moved beyond bring-up status with early gameplay/event coverage including water rush, conveyor, fan, block, door, water skim, miniboss work, and HCZ1-to-HCZ2 progression.
• S3K front-end and side modes expanded with title screen support, level select, Blue Ball special stage support, and active bonus-stage work across Gumball, Glowing Sphere/Pachinko, and Slots.
• Rendering, testing, and tooling all hardened further with trace replay testing, rendering-pipeline fixes, lifecycle/testability cleanup, and broader contributor documentation.
• OpenGGF remains an alpha release focused on preservation and accuracy. Sonic 1 is broadly playable, Sonic 2 remains the most complete module, and Sonic 3 & Knuckles has moved to a real AIZ-to-HCZ gameplay baseline but is still incomplete overall.

See CHANGELOG.md for full details.

Full Changelog: v0.4.20260304...v0.5.20260411