fix: Throw exception on deserialization failure in getAllApplicationDescriptors

Fixes #197

Changed HazelcastStateStore.getAllApplicationDescriptors() to throw
RuntimeException when any descriptor fails to deserialize, instead of
silently skipping failed descriptors and returning incomplete data.

Changes:
- Throw RuntimeException with clear message when deserialization fails
- Include application ID in error message
- Indicate cluster state may be corrupted
- Updated existing test to expect the exception
- Ensures callers are always aware of failures

This prevents silent data loss and ensures cluster state integrity.
Consistent with getApplicationDescriptor() behavior.

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

Author: Flossy

jplatform-cluster/src/main/java/org/flossware/jplatform/cluster/HazelcastStateStore.java

@@ -171,6 +171,7 @@ public ApplicationDescriptor getApplicationDescriptor(String applicationId) {
      * Creates a local snapshot and deserializes all descriptors.
      *
      * @return a map of application ID to descriptor
+     * @throws RuntimeException if any descriptor fails to deserialize
      */
     @Override
     public Map<String, ApplicationDescriptor> getAllApplicationDescriptors() {
@@ -183,6 +184,9 @@ public Map<String, ApplicationDescriptor> getAllApplicationDescriptors() {
                 result.put(entry.getKey(), descriptor);
             } catch (Exception e) {
                 logger.error("Failed to deserialize descriptor for: {}", entry.getKey(), e);
+                throw new RuntimeException(
+                    "Failed to deserialize application descriptor for " + entry.getKey() +
+                    " - cluster state may be corrupted", e);
             }
         }
 

jplatform-cluster/src/test/java/org/flossware/jplatform/cluster/HazelcastStateStoreTest.java

@@ -206,7 +206,7 @@ void testGetAllApplicationDescriptors() {
     }
 
     @Test
-    @DisplayName("Should skip invalid descriptors in getAllApplicationDescriptors")
+    @DisplayName("Should throw RuntimeException when encountering invalid JSON")
     void testGetAllApplicationDescriptorsWithInvalid() {
         // Given
         Map<String, String> jsonMap = new HashMap<>();
@@ -216,13 +216,12 @@ void testGetAllApplicationDescriptorsWithInvalid() {
 
         when(mockDescriptorMap.entrySet()).thenReturn(jsonMap.entrySet());
 
-        // When
-        Map<String, ApplicationDescriptor> descriptors = stateStore.getAllApplicationDescriptors();
+        // When / Then
+        RuntimeException exception = assertThrows(RuntimeException.class,
+                () -> stateStore.getAllApplicationDescriptors());
 
-        // Then
-        assertEquals(1, descriptors.size());
-        assertTrue(descriptors.containsKey("app1"));
-        assertFalse(descriptors.containsKey("app2"));
+        assertTrue(exception.getMessage().contains("Failed to deserialize application descriptor"));
+        assertTrue(exception.getMessage().contains("cluster state may be corrupted"));
     }
 
     @Test