Improve EmoTracker.Core performance, thread safety, and API flexibility

[emosaru]

Summary

• P1 — Cache type-tag lookups in JsonTypeTagsAttribute to avoid lock contention and full type scan on every deserialization call; rename CreateIntanceForTypeTag → CreateInstanceForTypeTag (typo fix)
• P5 — Fix ObservableCollectionExtensions.Sort O(n^2) by avoiding repeated IndexOf
• P6 — Use object lock instead of string literal "Registry" in TypeRegistry/TypedObjectRegistry to eliminate cross-type deadlock risk from string interning
• P7 — Fix TypedObjectRegistry null deref when ReflectionTypeLoadException.LoaderExceptions is null
• P8 — Add try/catch on TypeRegistry.GetTypes() to prevent crash on assemblies with missing dependencies
• A1 — Add Invoke<T>(Func<T>), Invoke(Func<Task>), BeginInvoke(Func<Task>) to dispatch service backend, eliminating TaskCompletionSource workarounds
• A2 — Add exception-aware Debug/Info/Warn/Error(Exception, ...) overloads to log service backend for structured logging support
• A3 — Add CancellationToken parameter and Cancel() method to all collection synchronizers and their derived classes
• T1 — Use Interlocked.Exchange for mActiveBackend in Log/Dispatch service backends to prevent TOCTOU race during backend swaps

Test plan

• Build solution: dotnet build EmoTracker/EmoTracker.csproj — passes clean
• Verify JsonTypeTagsAttribute.CreateInstanceForTypeTag works with cached dictionary for multiple type arguments
• Verify ObservableCollectionSynchronizerMT and BufferedObservableCollectionSynchronizerMT Cancel() overrides work
• Verify new dispatch overloads (Invoke<T>, Invoke(Func<Task>), BeginInvoke(Func<Task>)) work correctly in the UI
• Verify exception-aware logging (Log.Error(ex, ...)) forwards exception to Serilog correctly
• Verify TypeRegistry and TypedObjectRegistry don't crash when assemblies have missing dependencies

🤖 Generated with Claude Code