feat(seo): generate slugs for brands, categories and products, add GET /sitemap and the Postman collection

.gitignore

@@ -63,7 +63,12 @@ report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
 # Claude Code personal settings (.claude/settings.json stays shareable)
 /.claude/settings.local.json
 
-# Postman (skills fetched by `postman init`, personal workspace binding)
-/postman/
+# Postman: collections, specs and flows are versioned with the code.
+# Ignored: skills and SDKs (generated by the CLI), globals and environments (may hold personal values or secrets),
+# and .postman/ (binding to each developer's own workspace).
+/postman/*
+!/postman/collections/
+!/postman/specs/
+!/postman/flows/
 /.postman/
 /AGENTS.md