test(webapp): temporary CI diagnostics for empty session-agent .out

Logs the agent run rejection and, in EA1, dumps the collected .out parts
plus a direct out/records readback, to localize whether the agent's
writes reach S2 in CI or the read path returns empty. To be reverted.

Author: ericallam

apps/webapp/test/helpers/agentHarness.ts

@@ -112,6 +112,17 @@ export function runRealChatAgent(opts: RunRealChatAgentOptions): RunningAgent {
     ) as Promise<void>
   ).finally(restore);
 
+  done.catch((e) => {
+    const err = e instanceof Error ? e : new Error(String(e));
+    console.error(
+      "[AGENT-DIAG] run rejected",
+      opts.agentId,
+      runId,
+      `${err.name}: ${err.message}`,
+      (err.stack ?? "").split("\n").slice(1, 6).join(" || ")
+    );
+  });
+
   return {
     done,
     close: async () => {

apps/webapp/test/session-agent.e2e.test.ts

@@ -317,6 +317,20 @@ describe("session agent e2e (real chat.agent loop)", () => {
         maxMs: 30_000,
       });
 
+      const dbg = await fetch(
+        `${baseUrl}/realtime/v1/sessions/${encodeURIComponent(addressingKey)}/out/records`,
+        { headers: { Authorization: `Bearer ${token}` } }
+      );
+      console.error(
+        "[EA1-DIAG] collected parts:",
+        parts.length,
+        JSON.stringify(parts.map((p) => ({ id: p.id, chunk: p.chunk, headers: p.headers }))).slice(
+          0,
+          600
+        )
+      );
+      console.error("[EA1-DIAG] out/records readback:", dbg.status, (await dbg.text()).slice(0, 900));
+
       const text = parts
         .filter((p) => p.chunk != null)
         .map((p) => JSON.stringify(p.chunk))