docs: add backend documentation files

Reference guides (Sequelize model methods, Swagger) and migration reports
from the MongoDB-to-MySQL and domain-based route structure migrations.

docs/MIGRATION_SWAGGER_TODO.md

@@ -0,0 +1,19 @@
+
+# Swagger Path Updates Required
+
+The following Swagger YAML files need path updates:
+
+## skydive.yaml
+- Change: /api/v1/ → /api/skydive/
+- Affected routes: /jumps, /aeronefs, /dropzones, /canopies, /pages, /qcm, /applications
+
+## cms.yaml
+- Change: /api/v2/ → /api/cms/
+- Affected routes: /articles, /comments, /products, /tags, /profiles, /user
+
+## herowars.yaml
+- Change: /api/v3/ → /api/herowars/
+- Affected routes: /clans, /members
+- Note: Add herowars endpoint from former /api/v2/herowars
+
+Update in: src/config/swagger.js if paths are hardcoded.