chore: address final-review minors — surface event-consumer crashes, document IIFE-wrap heuristic, log shutdown failures, fix CHANGELOG file-size claim

Five tweaks from the whole-implementation review:
- session.ts: log unexpected event-consumer rejections instead of silent swallow
- client.ts: comment the return-substring IIFE-wrap false-positive case
- transport.ts: comment that ws.onclose post-open settle is no-op-by-design
- index.ts: log client.stop() failures during shutdown
- CHANGELOG.md: correct largest-file claim (transport.ts and client.ts are ~220 each, not "client.ts at ~180")

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/index.ts b/src/index.ts
index f5c7676..ee59f10 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -115,7 +115,13 @@ export default function browserHarnessExtension(pi: ExtensionAPI): void {
   pi.on("session_shutdown", async () => {
     persistState(pi, state);
     if (client) {
-      try { await client.stop(); } catch { /* best-effort */ }
+      try {
+        await client.stop();
+      } catch (e) {
+        // Shutdown is best-effort, but a stuck stop() points at a transport
+        // bug worth surfacing for debugging.
+        console.warn("[pi-browser-harness] client.stop() failed during shutdown:", e);
+      }
       client = null;
     }
     toolsRegistered = false;