feat: build codex-responses-api-proxy for all platforms as part of the GitHub Release (#4406)

This should make the `codex-responses-api-proxy` binaries available for
all platforms in a GitHub Release as well as a corresponding DotSlash
file.

Making `codex-responses-api-proxy` available as an `npm` module will be
done in a follow-up PR.

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/4404).
* __->__ #4406
* #4404
* #4403

.github/dotslash-config.json

@@ -27,6 +27,34 @@
           "path": "codex.exe"
         }
       }
+    },
+    "codex-responses-api-proxy": {
+      "platforms": {
+        "macos-aarch64": {
+          "regex": "^codex-responses-api-proxy-aarch64-apple-darwin\\.zst$",
+          "path": "codex-responses-api-proxy"
+        },
+        "macos-x86_64": {
+          "regex": "^codex-responses-api-proxy-x86_64-apple-darwin\\.zst$",
+          "path": "codex-responses-api-proxy"
+        },
+        "linux-x86_64": {
+          "regex": "^codex-responses-api-proxy-x86_64-unknown-linux-musl\\.zst$",
+          "path": "codex-responses-api-proxy"
+        },
+        "linux-aarch64": {
+          "regex": "^codex-responses-api-proxy-aarch64-unknown-linux-musl\\.zst$",
+          "path": "codex-responses-api-proxy"
+        },
+        "windows-x86_64": {
+          "regex": "^codex-responses-api-proxy-x86_64-pc-windows-msvc\\.exe\\.zst$",
+          "path": "codex-responses-api-proxy.exe"
+        },
+        "windows-aarch64": {
+          "regex": "^codex-responses-api-proxy-aarch64-pc-windows-msvc\\.exe\\.zst$",
+          "path": "codex-responses-api-proxy.exe"
+        }
+      }
     }
   }
 }