add JavaFX demo application

- Add FxMain as JavaFX application entry with IOC integration
- Add FxConfig with @Bean factory methods for DateTimeFormatter
- Add MainController with constructor injection
- Add UserService and MessageService layers
- Add main.fxml view with user management UI
- Add javafx-fxml dependency and javafx-maven-plugin
- Add demo documentation and run script
- Demonstrate @Controller, @Service, @Qualifier, @PostConstruct in JavaFX context

Run with: mvn javafx:run or run-javafx-demo.bat

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

run-javafx-demo.bat

@@ -0,0 +1,21 @@
+@echo off
+echo =====================================
+echo Timi-Inject JavaFX Demo
+echo =====================================
+echo.
+
+echo Compiling project...
+call mvn clean compile test-compile -Dmaven.test.skip=false -q
+if errorlevel 1 (
+    echo Compilation failed!
+    pause
+    exit /b 1
+)
+
+echo.
+echo Starting JavaFX application...
+echo.
+
+call mvn javafx:run
+
+pause