Add single-instance enforcement and DirectWrite crash workaround

- Implement mutex-based single instance check
- Show message if app is already running
- Force software rendering to prevent DirectWrite font initialization crash
- Update version to 1.0.2

Fixes:
- Multiple instances could run simultaneously
- DirectWrite crash on certain Windows configurations

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

NfcActions/NfcActions.csproj

@@ -7,9 +7,9 @@
     <UseWPF>true</UseWPF>
     <UseWindowsForms>true</UseWindowsForms>
     <ApplicationIcon>Resources\icon.ico</ApplicationIcon>
-    <Version>1.0.0</Version>
-    <AssemblyVersion>1.0.0.0</AssemblyVersion>
-    <FileVersion>1.0.0.0</FileVersion>
+    <Version>1.0.2</Version>
+    <AssemblyVersion>1.0.2.0</AssemblyVersion>
+    <FileVersion>1.0.2.0</FileVersion>
     <Company>Dangerous Things</Company>
     <Product>NFC Actions</Product>
     <Description>NFC card reader monitoring and action automation</Description>