Implement proper exception hierarchy and consistent error handling

- Create base exception classes:
  - VSSimulatorException: Base checked exception for all simulator errors
  - VSSimulatorRuntimeException: Base unchecked exception for unrecoverable errors
- Refactor existing exceptions to extend from base class:
  - VSEventNotCopyableException: Now includes better error messages
  - VSParseIntegerVectorException: Added constructors with cause support
  - VSNegativeNumberException: Added field name and value parameters
- Add new specific exception types:
  - VSConfigurationException: For configuration errors
  - VSSerializationException: For save/load operations
  - VSProcessException: For process-related errors
  - VSProtocolException: For protocol execution errors
- Create VSErrorHandler utility class:
  - Centralized error logging and user notification
  - Consistent error handling patterns
  - Helper methods for warning and error dialogs
- Update exception handling in code:
  - VSClassLoader: Better error messages and specific exception handling
  - Timestamp events: Catch RuntimeException for custom actions
- All 132 unit tests pass

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

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

1 files changed, 47 insertions, 0 deletions

diff --git a/src/main/java/exceptions/VSSimulatorRuntimeException.java b/src/main/java/exceptions/VSSimulatorRuntimeException.java
new file mode 100644
index 0000000..59acac9
--- /dev/null
+++ b/src/main/java/exceptions/VSSimulatorRuntimeException.java
@@ -0,0 +1,47 @@
+package exceptions;
+
+/**
+ * Base runtime exception class for DS-Sim simulator.
+ * Used for unrecoverable errors that should not be caught in normal flow.
+ *
+ * @author Paul C. Buetow
+ */
+public class VSSimulatorRuntimeException extends RuntimeException {
+    /** The serial version uid */
+    private static final long serialVersionUID = 1L;
+    
+    /**
+     * Constructs a new simulator runtime exception with null as its detail message.
+     */
+    public VSSimulatorRuntimeException() {
+        super();
+    }
+    
+    /**
+     * Constructs a new simulator runtime exception with the specified detail message.
+     *
+     * @param message the detail message
+     */
+    public VSSimulatorRuntimeException(String message) {
+        super(message);
+    }
+    
+    /**
+     * Constructs a new simulator runtime exception with the specified detail message and cause.
+     *
+     * @param message the detail message
+     * @param cause the cause
+     */
+    public VSSimulatorRuntimeException(String message, Throwable cause) {
+        super(message, cause);
+    }
+    
+    /**
+     * Constructs a new simulator runtime exception with the specified cause.
+     *
+     * @param cause the cause
+     */
+    public VSSimulatorRuntimeException(Throwable cause) {
+        super(cause);
+    }
+}
\ No newline at end of file