feat(#1970): add POST /api/github-account dashboard endpoint for the credentials UI

hive-c0re/src/dashboard/matrix_accounts.rs

@@ -262,6 +262,45 @@ pub(super) async fn post_matrix_account_login(Form(f): Form<MatrixLoginForm>) ->
     axum::Json(MatrixLoginResult { ok: true, user_id }).into_response()
 }
 
+/// Form body for `POST /api/github-account` (urlencoded, the dashboard's
+/// mutation convention). Writes the operator-supplied PAT to the agent's
+/// `github-token` file. The GitHub counterpart of the matrix login form, but
+/// far simpler: no account creation, no homeserver, no login modes — the
+/// operator pastes a PAT for an existing account.
+#[derive(Deserialize)]
+pub(super) struct GithubAccountForm {
+    agent: String,
+    token: String,
+}
+
+#[derive(Serialize)]
+struct GithubAccountResult {
+    ok: bool,
+}
+
+/// Provision (or refresh) an agent's GitHub PAT from the dashboard
+/// credentials tab. Validates the agent name, then writes the PAT to
+/// `<state>/github-token` (`0600`, agent-owned) via hive-priv. No account
+/// creation and no daemon to kick — the agent's `gh` wrapper / git credential
+/// helper read the file live, so the new token takes effect immediately.
+/// Operator-authenticated (dashboard). Never echoes the token back — only
+/// `{ ok: true }`.
+pub(super) async fn post_github_account(Form(f): Form<GithubAccountForm>) -> Response {
+    let agent = f.agent.trim();
+    let token = f.token.trim();
+    if !is_plain_ident(agent) {
+        return error_response(&format!("github-account: invalid agent {agent:?}"));
+    }
+    if token.is_empty() {
+        return error_response("github-account: token is required");
+    }
+    if let Err(e) = crate::priv_client::write_agent_github_token(agent, token).await {
+        return error_response(&format!("github-account: write token failed: {e:#}"));
+    }
+    tracing::info!(%agent, "github-account: provisioned github PAT");
+    axum::Json(GithubAccountResult { ok: true }).into_response()
+}
+
 /// POST `m.login.password` to `<homeserver>/_matrix/client/v3/login`.
 /// Returns `(access_token, user_id)`.
 async fn matrix_password_login(

hive-c0re/src/dashboard/mod.rs

@@ -188,6 +188,10 @@ pub async fn serve(port: u16, coord: Arc<Coordinator>) -> Result<()> {
             "/api/matrix-account-login",
             post(matrix_accounts::post_matrix_account_login),
         )
+        .route(
+            "/api/github-account",
+            post(matrix_accounts::post_github_account),
+        )
         .route(
             "/api/cancel-reminder/{id}",
             post(reminders::post_cancel_reminder),