refactor: réorganiser Dockerfiles et scripts par module

Réorganise la structure Docker pour plus de cohérence dans le monorepo.
Chaque module (backend, docs) a maintenant ses propres Dockerfiles et scripts.

Changements:
- backend/docker/ : Dockerfile (prod) + dev.Dockerfile (hot reload) + init script
- docs/docker/ : mkdocs.Dockerfile + pdf.Dockerfile
- docs/scripts/ : generate-bdd-docs.py + generate-pdf-docs.py
- Déplace docker-compose.yml dans backend/
- Supprime scripts obsolètes (fix-markdown-*.sh, remove-broken-links.sh)
- Déplace .dockerignore à la racine
- Met à jour Makefile avec nouveaux chemins

Organisation finale:
- backend/ : tout ce qui concerne l'API backend
- docs/ : tout ce qui concerne la documentation
- scripts/ : uniquement setup.sh (scripts généraux du projet)

Makefile

@@ -71,13 +71,13 @@ clean:
 docs-clean:
 	@echo "$(YELLOW)Cleaning generated documentation...$(NC)"
 	@rm -rf docs/generated/
-	@docker rmi roadwave-pdf-generator 2>/dev/null || true
+	@docker rmi roadwave-pdf-generator roadwave-mkdocs 2>/dev/null || true
 	@echo "$(GREEN)✓ Documentation cleaned$(NC)"
 
 ## docker-up: Start all Docker services
 docker-up:
 	@echo "$(BLUE)Starting Docker services...$(NC)"
-	@docker compose up -d
+	@cd backend && docker compose up -d
 	@echo "$(GREEN)✓ Services started$(NC)"
 	@echo "$(YELLOW)API:      http://localhost:8080$(NC)"
 	@echo "$(YELLOW)Zitadel:  http://localhost:8081$(NC)"
@@ -86,12 +86,12 @@ docker-up:
 ## docker-down: Stop all Docker services
 docker-down:
 	@echo "$(YELLOW)Stopping Docker services...$(NC)"
-	@docker compose down
+	@cd backend && docker compose down
 	@echo "$(GREEN)✓ Services stopped$(NC)"
 
 ## docker-logs: Show Docker logs
 docker-logs:
-	@docker compose logs -f
+	@cd backend && docker compose logs -f
 
 ## migrate-up: Apply all migrations
 migrate-up:
@@ -151,30 +151,34 @@ run-api:
 
 ## docs-serve: Start documentation server (http://localhost:8000)
 docs-serve:
+	@echo "$(BLUE)Building MkDocs Docker image with plugins...$(NC)"
+	@docker build -t roadwave-mkdocs -f docs/docker/mkdocs.Dockerfile . -q
 	@echo "$(BLUE)Generating BDD documentation from Gherkin files...$(NC)"
-	@python3 scripts/generate-bdd-docs.py
+	@python3 docs/scripts/generate-bdd-docs.py
 	@echo "$(GREEN)✓ BDD documentation generated$(NC)"
 	@echo "$(BLUE)Starting documentation server...$(NC)"
 	@echo "$(YELLOW)Documentation available at http://localhost:8000$(NC)"
-	@docker run --rm -it -p 8000:8000 -v "$(PWD):/docs" squidfunk/mkdocs-material
+	@docker run --rm -p 8000:8000 -v "$(PWD):/docs" roadwave-mkdocs
 
 ## bdd-docs: Generate BDD docs from Gherkin and serve with MkDocs (http://localhost:8000)
 bdd-docs:
+	@echo "$(BLUE)Building MkDocs Docker image with plugins...$(NC)"
+	@docker build -t roadwave-mkdocs -f docs/docker/mkdocs.Dockerfile . -q
 	@echo "$(BLUE)Generating BDD documentation from Gherkin files...$(NC)"
-	@python3 scripts/generate-bdd-docs.py
+	@python3 docs/scripts/generate-bdd-docs.py
 	@echo "$(GREEN)✓ BDD documentation generated$(NC)"
 	@echo "$(BLUE)Starting documentation server...$(NC)"
 	@echo "$(YELLOW)Documentation available at http://localhost:8000$(NC)"
 	@echo "$(YELLOW)Navigate to 'Tests BDD' section$(NC)"
-	@docker run --rm -it -p 8000:8000 -v "$(PWD):/docs" squidfunk/mkdocs-material
+	@docker run --rm -p 8000:8000 -v "$(PWD):/docs" roadwave-mkdocs
 
 ## docs-pdf: Generate PDF of all documentation (output/RoadWave_Documentation.pdf)
 docs-pdf:
 	@echo "$(BLUE)Generating BDD documentation from Gherkin files...$(NC)"
-	@python3 scripts/generate-bdd-docs.py
+	@python3 docs/scripts/generate-bdd-docs.py
 	@echo "$(GREEN)✓ BDD documentation generated$(NC)"
 	@echo "$(BLUE)Building PDF generator Docker image...$(NC)"
-	@docker build -t roadwave-pdf-generator -f scripts/Dockerfile.pdf . -q
+	@docker build -t roadwave-pdf-generator -f docs/docker/pdf.Dockerfile . -q
 	@echo "$(BLUE)Generating PDF documentation...$(NC)"
 	@docker run --rm -u $(shell id -u):$(shell id -g) -v "$(PWD):/docs" roadwave-pdf-generator
 	@echo "$(GREEN)✓ PDF generated: output/RoadWave_Documentation.pdf$(NC)"