fix: emit error/exit events before closing session scope and remove dead code

- Move emit calls for runtime.error and session.exited before
  stopOpenCodeContext in emitUnexpectedExit. The scope close interrupts
  the event-pump fiber that is executing the function, so events emitted
  after the close are silently dropped.
- Remove unused isProviderAdapterProcessError variable (dead code from
  the Schema.is refactor).

Author: cursoragent

apps/server/src/provider/Layers/OpenCodeAdapter.ts

@@ -95,7 +95,6 @@ function nowIso(): string {
 }
 
 const isProviderAdapterRequestError = Schema.is(ProviderAdapterRequestError);
-const isProviderAdapterProcessError = Schema.is(ProviderAdapterProcessError);
 
 function buildEventBase(input: {
   readonly threadId: ThreadId;
@@ -473,7 +472,12 @@ export function makeOpenCodeAdapterLive(options?: OpenCodeAdapterLiveOptions) {
         }
         const turnId = context.activeTurnId;
         sessions.delete(context.session.threadId);
-        yield* stopOpenCodeContext(context);
+        // Emit error and exit events *before* closing the session scope.
+        // `stopOpenCodeContext` closes `context.sessionScope`, which
+        // interrupts every fiber forked into it — including the event-pump
+        // fiber that may be running this function. Emitting after the close
+        // would silently drop these events because the fiber observes the
+        // pending interruption at the next yield point.
         yield* emit({
           ...buildEventBase({ threadId: context.session.threadId, turnId }),
           type: "runtime.error",
@@ -491,6 +495,7 @@ export function makeOpenCodeAdapterLive(options?: OpenCodeAdapterLiveOptions) {
             exitKind: "error",
           },
         }).pipe(Effect.ignore);
+        yield* stopOpenCodeContext(context);
       });
 
       /** Emit content.delta and item.completed events for an assistant text part. */