fix(pi): upstream completion test sends a sessionId (OpenCode x-opencode-session)

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/agent/src/pi/upstream.ts

@@ -356,7 +356,14 @@ export class PiUpstreamClient {
         res = await this.models.completeSimple(
           { ...model, maxTokens: Math.min(model.maxTokens || 16, 16) },
           { messages: [{ role: "user", content: "Reply with: ok", timestamp: Date.now() }] },
-          { maxTokens: 16, ...(opts.signal ? { signal: opts.signal } : {}), timeoutMs: 30_000, maxRetries: 0 },
+          {
+            maxTokens: 16,
+            ...(opts.signal ? { signal: opts.signal } : {}),
+            timeoutMs: 30_000,
+            maxRetries: 0,
+            // OpenCode(Zen / Go)按会话路由,缺 x-opencode-session 会被拒;其余 provider 用它做缓存键,无副作用
+            sessionId: `umt-upstream-test-${crypto.randomUUID()}`,
+          },
         );
       } catch (err) {
         throw classifyUpstreamError(err);