fix: blank assistant text with MCP enabled after AI SDK v6 migration

The v6 upgrade changed the default unmapped finish reason from "unknown"
to "other", but the prompt loop continue sets were not updated to match.
This caused premature loop exit after MCP tool calls, before the model
produced final assistant text.

Fixes #20050
Fixes #20465

Author: kostiantyn-kugot

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -1359,7 +1359,7 @@ function AssistantMessage(props: { message: AssistantMessage; parts: Part[]; las
   const model = createMemo(() => Model.name(ctx.providers(), props.message.providerID, props.message.modelID))
 
   const final = createMemo(() => {
-    return props.message.finish && !["tool-calls", "unknown"].includes(props.message.finish)
+    return props.message.finish && !["tool-calls", "other"].includes(props.message.finish)
   })
 
   const duration = createMemo(() => {

packages/opencode/src/session/prompt.ts

@@ -1438,7 +1438,7 @@ NOTE: At any point in time through this workflow you should feel free to ask the
 
           if (
             lastAssistant?.finish &&
-            !["tool-calls"].includes(lastAssistant.finish) &&
+            !["tool-calls", "other"].includes(lastAssistant.finish) &&
             !hasToolCalls &&
             lastUser.id < lastAssistant.id
           ) {
@@ -1593,7 +1593,7 @@ NOTE: At any point in time through this workflow you should feel free to ask the
               return "break" as const
             }
 
-            const finished = handle.message.finish && !["tool-calls", "unknown"].includes(handle.message.finish)
+            const finished = handle.message.finish && !["tool-calls", "other"].includes(handle.message.finish)
             if (finished && !handle.message.error) {
               if (format.type === "json_schema") {
                 handle.message.error = new MessageV2.StructuredOutputError({