fix(changesets): rename stale @cipherstash/cli package key to stash

The CLI package was renamed from `@cipherstash/cli` to `stash` in
packages/cli/package.json, but two changesets still referenced the
old name. The changesets/version action on main fails with:

  Found changeset cli-runner-aware-help-banners for package
  @cipherstash/cli which is not in the workspace

Updates both frontmatter keys to the current package name. Body copy
that mentions `@cipherstash/cli` historically is left intact —
changesets only validates the YAML frontmatter package keys.

Author: calvinbrewer

.changeset/cli-runner-aware-help-banners.md

@@ -1,5 +1,5 @@
 ---
-'@cipherstash/cli': patch
+'stash': patch
 ---
 
 Make `--help` banners and the post-install "Next steps" panel show commands using the package manager the user actually invoked the CLI with, instead of always emitting `npx`.

.changeset/package-manager-aware-output.md

@@ -1,5 +1,5 @@
 ---
-"@cipherstash/cli": patch
+"stash": patch
 "@cipherstash/wizard": patch
 "@cipherstash/protect": patch
 "@cipherstash/drizzle": patch