Release 1.1.6

feat: refactor JSON API and migrate yyjson integration

• Break IJsonManager ABI: remove std::variant, split signed/unsigned APIs,
  add uint64 support for object/array/root/pointer access.
• Replace void*/yyjson iterators with typed key/value/removal APIs.
• Remove deprecated Foreach* and PtrTryGetVal natives.
• Rename Release → ReleaseJsonValue; add ReleaseString for WriteToStringPtr.
• Add error-buffer params to all major API paths; return null/false on failure.
• Add ToStringDirect (zero-alloc) and route serialized cleanup via ReleaseString.
• Centralize pointer resolution, mutation, and patch execution into helpers.
• Extract RefCounted/RefPtr to RefCounted.h; extract type/container helpers to JsonTemplates.h.
• Improve signed/unsigned, uint64, integer parsing, and FP comparison (NaN/inf/tolerance).
• Validate negative SourcePawn array/index/buffer sizes before conversion.
• Replace yyjson with a submodule.
• Update tests, benchmarks, README, build docs, and project URLs.
• Bump IJsonManager interface version from 3 to 4.