Update project version to 2.0.0 and release notes

Author: Nonanti

MathFlow.Core/MathFlow.Core.csproj

@@ -6,7 +6,7 @@
     <Nullable>enable</Nullable>
     <GeneratePackageOnBuild>false</GeneratePackageOnBuild>
     <PackageId>MathFlow</PackageId>
-    <Version>1.1.0</Version>
+    <Version>2.0.0</Version>
     <Authors>Nonanti</Authors>
     <Description>C# math expression library with symbolic computation support. Parse, evaluate, differentiate, simplify mathematical expressions.</Description>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
@@ -19,7 +19,7 @@
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <PackageIcon>icon.png</PackageIcon>
     <Copyright>Copyright (c) 2025 Nonanti</Copyright>
-    <PackageReleaseNotes>Initial release with core mathematical functionality</PackageReleaseNotes>
+    <PackageReleaseNotes>v2.0.0: Complex numbers, enhanced polynomial factoring, new ODE solvers, rational function integration, matrix operations</PackageReleaseNotes>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <IncludeSymbols>true</IncludeSymbols>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>