fix: prevent multi-round annotation processing bug

[wassertim]

Summary

Fixes #6 - Prevents multi-round annotation processing bug where List<Integer> fields incorrectly generated ListMapper dependencies.

Problem

The annotation processor was running in multiple rounds:

1. First round: Generated correct inline NUMBER_LIST mapping for List<Integer>
2. Second round: Regenerated files with incorrect ListMapper dependency
3. Type information from javax.lang.model API behaves differently between rounds

This caused UnsatisfiedResolutionException: Unsatisfied dependency for type ListMapper when starting Quarkus applications.

Solution

Modified AnnotationProcessor.java to only process in the first round:

• Added Set<String> processedTypes to track already-processed types
• Skip processing if roundEnv.processingOver() returns true (final round)
• Skip processing if roundEnv.getRootElements().isEmpty() (subsequent round with no new sources)
• Skip processing if !processedTypes.isEmpty() (already processed in first round)

Added DEBUG_MARKER to MapperGenerator.java for build verification.

Testing

✅ Verified no ListMapper references in generated code
✅ Confirmed inline NUMBER_LIST mapping for List<Integer> fields:

if (routeInstruction.getWaypointIndices() != null) {
    List<AttributeValue> waypointIndicesList = routeInstruction.getWaypointIndices().stream()
        .map(val -> AttributeValue.builder().n(String.valueOf(val)).build())
        .collect(Collectors.toList());
    attributes.put("waypointIndices", AttributeValue.builder().l(waypointIndicesList).build());
}

✅ Single timestamp in generated files (processor runs only once)
✅ DEBUG_MARKER present showing local build is being used

Files Changed

• src/main/java/com/github/wassertim/dynamodb/toolkit/processor/AnnotationProcessor.java
• src/main/java/com/github/wassertim/dynamodb/toolkit/generation/MapperGenerator.java

Closes #6