re-enable Prettier check for codex-cli in CI (#417)

This check was lost in https://github.com/openai/codex/pull/287. Both
the root folder and `codex-cli/` have their own `pnpm format` commands
that check the formatting of different things.

Also ran `pnpm format:fix` to fix the formatting violations that got in
while this was disabled in CI.

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[//]: # (BEGIN SAPLING FOOTER)
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with [ReviewStack](https://reviewstack.dev/openai/codex/pull/417).
* #420
* #419
* #416
* __->__ #417

.github/workflows/ci.yml

@@ -44,7 +44,11 @@ jobs:
 
       # Run all tasks using workspace filters
 
-      - name: Check formatting
+      - name: Check TypeScript code formatting
+        working-directory: codex-cli
+        run: pnpm run format
+
+      - name: Check Markdown and config file formatting
         run: pnpm run format
 
       - name: Run tests