chore: clean up content phase organization

apps/docs/redirects.ts

@@ -16,6 +16,7 @@ export default [
   { from: "/48", to: "/matrix-index-math/rotate-image" },
   { from: "/49", to: "/hash-table/group-anagrams" },
   { from: "/54", to: "/matrix-index-math/spiral-matrix" },
+  { from: "/70", to: "/1d-dynamic-programming/climbing-stairs" },
   { from: "/73", to: "/matrix-index-math/set-matrix-zeroes" },
   { from: "/74", to: "/binary-search/search-a-2d-matrix" },
   { from: "/78", to: "/backtracking/subsets" },