(feat) add functions to manage GitHub repository variables

Author: paoloanzn

cli/src/github/vars.ts

@@ -0,0 +1,36 @@
+import type { Octokit } from "@octokit/core";
+
+// standard github REST API headers
+const HEADERS = {
+    accept: "application/vnd.github+json",
+    "X-Github-Api-Version": "2026-03-10",
+}
+
+// metadata looks like: { name, value, created_at, updated_at ... }
+export async function getRepoVariableMetadata(client: Octokit, repoName: string, repoOwnerName: string, variableName: string): Promise<any> {
+    const res = await client.request(
+        "GET /repos/{owner}/{repo}/actions/variables/{name}",
+        { owner: repoOwnerName, repo: repoName, name: variableName, headers: HEADERS},
+    );
+    return res.data;
+}
+
+export async function setRepoVariable(client: Octokit, repoName: string, repoOwnerName: string, variableName: string, value: string): Promise<void> {
+    try {
+        await client.request(
+            "PATCH /repos/{owner}/{repo}/actions/variables/{name}",
+            { owner: repoOwnerName, repo: repoName, name: variableName, value, headers: HEADERS},
+        );
+    } catch (err) {
+        if (!isNotFoundError(err)) throw err;
+
+        await client.request(
+            "POST /repos/{owner}/{repo}/actions/variables",
+            { owner: repoOwnerName, repo: repoName, name: variableName, value, headers: HEADERS},
+        );
+    }
+}
+
+function isNotFoundError(err: unknown): boolean {
+    return typeof err === "object" && err !== null && "status" in err && err.status === 404;
+}