fix(opencode): show child session prompts (#4055)

Show OpenCode child-session user prompts even when the text part has no completion timestamp.

packages/app/e2e/browser/provider-subagents.real.spec.ts

@@ -43,7 +43,6 @@ const cases: ProviderSubagentCase[] = [
     sentinel: "OPENCODE_CHILD_SENTINEL",
     expectedName: "Verify OpenCode descriptor",
     expectedSubtitle: /explore · gpt-5\.4(?: · [^\n·]+)? · \d+(?:\.\d+)?k? tokens/i,
-    expectsUserMessage: false,
     providerConfig: { model: "openai/gpt-5.4" },
     prompt:
       'Use the task tool exactly once with description "Verify OpenCode descriptor" and the explore subagent. Ask it to reply with exactly OPENCODE_CHILD_SENTINEL and do nothing else. Wait for it, then reply ROOT_DONE.',

packages/server/src/server/agent/providers/opencode-agent.test.ts

@@ -6361,7 +6361,7 @@ describe("OpenCode provider subagent contract", () => {
           messageID: "msg_child_prompt",
           type: "text",
           text: "Inspect the auth flow.",
-          time: { start: 1, end: 2 },
+          time: { start: 1 },
         },
       },
     });

packages/server/src/server/agent/providers/opencode-agent.ts

@@ -2811,7 +2811,7 @@ function appendOpenCodeTextPart(
   events: AgentStreamEvent[],
 ): void {
   if (messageRole === "user") {
-    if (!part.time?.end || !part.text || state.emittedUserMessageIds?.has(part.messageID)) {
+    if (!part.text || state.emittedUserMessageIds?.has(part.messageID)) {
       return;
     }
     state.emittedUserMessageIds?.add(part.messageID);