[mikasoukhov]

Actual runtime changes (same PR, no master merge)

Ecng.Common

• TypeHelper.CreateInstance uses registered, statically compiled constructors before the original reflection fallback.
• TypeHelper.Make resolves precompiled closed generic types from a concurrent structural registry, avoiding a global lock and repeated candidate metadata arrays.
• ArrayHelper.CreateArray now uses static factories for common element types out of the box and allows explicit registration for model arrays.
• Converter.ArrayCovariance routes array creation through the same AOT-safe path.
• Converter.RegisterTypeName resolves pre-registered model types before assembly scanning.
• FastActivator<T> supports explicit delegates and avoids Reflection.Emit and constructor inspection on Native AOT.

Ecng.Serialization

• Existing SettingsStorage sync/async persistable creation now goes through the registered factory path.
• Existing JsonSerializer list/array materialization uses precompiled generic types, constructors and array factories.
• JArrayToObjectConverter<T> now supports explicit precompiled field accessors in wire order, avoiding Reflection.Emit and runtime field metadata assumptions. JIT reflection fallback remains unchanged.
• JsonHelper provides source-generated JSON metadata overloads; non-generic variants are limited to net7+ to preserve net6 support.
• JSON reflection field scanning is annotated for trimming.

Ecng.Reflection

• FindImplementations<T> uses RegisterImplementation<TContract,TImplementation> registrations in Native AOT rather than scanning loaded assemblies. JIT scanning stays available.

Verification

• Dedicated workflow audits Ecng.Common and Serialization for IL2xxx/IL3xxx warnings, includes a net6 compilation check, builds net10 native executable and executes smoke tests.
• Smoke exercises the actual legacy settings, collection serializer, static implementation discovery, field-based JSON and source-generated JSON paths.
• Regular cross-platform .NET tests run separately.
• Historical legacy Newtonsoft and unregistered reflection APIs still carry AOT warnings; this PR does NOT claim all Ecng APIs to be universally AOT-safe.
• Keep PR draft until the most recent commit passes native and standard CI. No blanket NoWarn and no change to NuGet release workflow.