Refactor constants management to use Pydantic BaseModel for configuration

- Replaced module-level path variables in constants.py with a structured Pydantic Config class.
- Updated all relevant modules (train.py, augmentation.py, exports.py, dataset-visualiser.py, manual_run.py) to access paths through the new config structure.
- Fixed bugs related to image processing and model saving.
- Enhanced test infrastructure to accommodate the new configuration approach.

This refactor improves code maintainability and clarity by centralizing configuration management.

_docs/02_document/state.json

@@ -0,0 +1,22 @@
+{
+  "current_step": "complete",
+  "completed_steps": ["discovery", "module-analysis", "component-assembly", "system-synthesis", "verification", "solution-extraction", "problem-extraction", "final-report"],
+  "focus_dir": null,
+  "modules_total": 21,
+  "modules_documented": [
+    "constants", "utils", "security", "hardware_service", "cdn_manager",
+    "dto/annotationClass", "dto/imageLabel", "inference/dto", "inference/onnx_engine",
+    "api_client", "augmentation", "inference/tensorrt_engine", "inference/inference",
+    "exports", "convert-annotations", "dataset-visualiser",
+    "train", "start_inference",
+    "manual_run",
+    "annotation-queue/annotation_queue_dto", "annotation-queue/annotation_queue_handler"
+  ],
+  "modules_remaining": [],
+  "module_batch": 7,
+  "components_written": [
+    "01_core", "02_security", "03_api_cdn", "04_data_models",
+    "05_data_pipeline", "06_training", "07_inference", "08_annotation_queue"
+  ],
+  "last_updated": "2026-03-26T00:00:00Z"
+}