chore: remove the TypeScript code from the repository (#2048)

This deletes the bulk of the `codex-cli` folder and eliminates the logic
that builds the TypeScript code and bundles it into the release.

Since this PR modifies `.github/workflows/rust-release.yml`, to test
changes to the release process, I locally commented out all of the "is
this commit on upstream `main`" checks in
`scripts/create_github_release.sh` and ran:

```
./codex-rs/scripts/create_github_release.sh 0.20.0-alpha.4
```

Which kicked off:

https://github.com/openai/codex/actions/runs/16842085113

And the release artifacts appear legit!

https://github.com/openai/codex/releases/tag/rust-v0.20.0-alpha.4

patches/marked-terminal@7.3.0.patch

@@ -1,26 +0,0 @@
-diff --git a/index.js b/index.js
-index 5e2d4b4f212a7c614ebcd5cba8c4928fa3e0d2d0..24dba3560bee4f88dac9106911ef204f37babebe 100644
---- a/index.js
-+++ b/index.js
-@@ -83,7 +83,7 @@ Renderer.prototype.space = function () {
- 
- Renderer.prototype.text = function (text) {
-   if (typeof text === 'object') {
--    text = text.text;
-+    text = text.tokens ? this.parser.parseInline(text.tokens) : text.text;
-   }
-   return this.o.text(text);
- };
-@@ -185,10 +185,10 @@ Renderer.prototype.listitem = function (text) {
-   }
-   var transform = compose(this.o.listitem, this.transform);
-   var isNested = text.indexOf('\n') !== -1;
--  if (isNested) text = text.trim();
-+  if (!isNested) text = transform(text);
- 
-   // Use BULLET_POINT as a marker for ordered or unordered list item
--  return '\n' + BULLET_POINT + transform(text);
-+  return '\n' + BULLET_POINT + text;
- };
- 
- Renderer.prototype.checkbox = function (checked) {