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.

.cursor/skills/refactor/phases/02-analysis.md

@@ -0,0 +1,41 @@
+# Phase 2: Analysis
+
+**Role**: Researcher and software architect
+**Goal**: Research improvements and produce a refactoring roadmap
+**Constraints**: Analysis only — no code changes
+
+## 2a. Deep Research
+
+1. Analyze current implementation patterns
+2. Research modern approaches for similar systems
+3. Identify what could be done differently
+4. Suggest improvements based on state-of-the-art practices
+
+Write `REFACTOR_DIR/analysis/research_findings.md`:
+- Current state analysis: patterns used, strengths, weaknesses
+- Alternative approaches per component: current vs alternative, pros/cons, migration effort
+- Prioritized recommendations: quick wins + strategic improvements
+
+## 2b. Solution Assessment
+
+1. Assess current implementation against acceptance criteria
+2. Identify weak points in codebase, map to specific code areas
+3. Perform gap analysis: acceptance criteria vs current state
+4. Prioritize changes by impact and effort
+
+Write `REFACTOR_DIR/analysis/refactoring_roadmap.md`:
+- Weak points assessment: location, description, impact, proposed solution
+- Gap analysis: what's missing, what needs improvement
+- Phased roadmap: Phase 1 (critical fixes), Phase 2 (major improvements), Phase 3 (enhancements)
+
+**Self-verification**:
+- [ ] All acceptance criteria are addressed in gap analysis
+- [ ] Recommendations are grounded in actual code, not abstract
+- [ ] Roadmap phases are prioritized by impact
+- [ ] Quick wins are identified separately
+
+**Save action**: Write analysis artifacts
+
+**BLOCKING**: Present refactoring roadmap to user. Do NOT proceed until user confirms.
+
+**Quick Assessment mode stops here.** Present final summary and write `FINAL_report.md` with phases 0-2 content.