fix: a run started a moment ago is never judged dead — another dashboard's tmux list may predate it

Only the process that starts a pane writes it into its own cached tmux list
(noteSession); a second dashboard on the same database (a dev server) holds
a member list up to 15 s old, so its heal beat ended a Codex pane seconds
after it started and the proxy gateway answered 401. reconcileOrphans and
healRunId skip a run younger than 20 s (dashboard-runs.isYoungRun).
Tests: dashboard-runs (young vs old).

server/lib/dashboard-runs.js

@@ -258,8 +258,21 @@ function claimToolSessions(sessionId = null) {
 }
 
 const runningStmt = db.prepare(
-  "SELECT id, tool, session_id, cwd FROM dashboard_runs WHERE status IN ('running', 'spawning')"
+  "SELECT id, tool, session_id, cwd, started_at FROM dashboard_runs WHERE status IN ('running', 'spawning')"
 );
+
+/**
+ * How long a new run is never judged dead. A tmux list is a cached answer —
+ * a member's may be up to 15 s old (tmux.js MEMBER_LIST_MAX_AGE_MS) — and only
+ * the process that started a pane writes it into its own cache, so another
+ * dashboard on the same database (a dev server) ended a pane it had simply
+ * not listed yet: the proxy gateway then answered 401 to a live Codex.
+ */
+const YOUNG_RUN_MS = 20_000;
+function isYoungRun(startedAt, now = Date.now()) {
+  const t = Date.parse(startedAt || "");
+  return Number.isFinite(t) && now - t < YOUNG_RUN_MS;
+}
 const endStmt = db.prepare(`
   UPDATE dashboard_runs
   SET status = @status,
@@ -300,7 +313,7 @@ function reconcileOrphans(isAlive = () => false) {
     let changes = 0;
     const { unseenMemberFolder } = require("./linux-accounts");
     for (const row of runningStmt.all()) {
-      if (isAlive(row.id) || unseenMemberFolder(row.cwd)) continue;
+      if (isAlive(row.id) || unseenMemberFolder(row.cwd) || isYoungRun(row.started_at)) continue;
       const interrupted =
         row.tool !== "shell" &&
         !!row.session_id &&
@@ -368,6 +381,7 @@ module.exports = {
   getRun,
   forgetShellRun,
   reconcileOrphans,
+  isYoungRun,
   listInterrupted,
   dismissInterrupted,
   proxyForSession,