fix: use scoped package name in changesets

Release CI failed because two changesets referenced "codemap" instead of "@stainless-code/codemap".

Author: SutuSebastian

.changeset/fix-prepublish-check-validation.md

@@ -1,5 +1,5 @@
 ---
-"codemap": patch
+"@stainless-code/codemap": patch
 ---
 
 Run full `check` (not build-only) in `prepublishOnly` so npm publish cannot skip tests or typecheck.

.changeset/fix-worker-count-env-validation.md

@@ -1,5 +1,5 @@
 ---
-"codemap": patch
+"@stainless-code/codemap": patch
 ---
 
 Reject malformed `CODEMAP_PARSE_WORKERS` values (e.g. `2abc`, `1.5`) instead of silently truncating with `parseInt`.