chore(rs): update dependencies (#1494)

### Chores
- Update cargo dependencies
- Remove unused cargo dependencies
- Fix clippy warnings
- Update Dockerfile (package.json requires node 22)
- Let Dependabot update bun, cargo, devcontainers, docker,
github-actions, npm (nix still not supported)

### TODO
- Upgrade dependencies with breaking changes

```shell
$ cargo update --verbose
   Unchanged crossterm v0.28.1 (available: v0.29.0)
   Unchanged schemars v0.8.22 (available: v1.0.4)
```

.github/dependabot.yaml

@@ -0,0 +1,32 @@
+# https://docs.github.com/en/code-security/dependabot/working-with-dependabot/dependabot-options-reference#package-ecosystem-
+
+version: 2
+updates:
+  - package-ecosystem: bun
+    directory: .github/actions/codex
+    schedule:
+      interval: weekly
+  - package-ecosystem: cargo
+    directories:
+      - codex-rs
+      - codex-rs/*
+    schedule:
+      interval: weekly
+  - package-ecosystem: devcontainers
+    directory: /
+    schedule:
+      interval: weekly
+  - package-ecosystem: docker
+    directory: codex-cli
+    schedule:
+      interval: weekly
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+  - package-ecosystem: npm
+    directories:
+      - /
+      - codex-cli
+    schedule:
+      interval: weekly