fix(cli): persist defaulted finish reason so loop break check sees it

The loop reloads messages from storage at the top of each iteration via filterCompactedEffect, so an in-memory mutation on handle.message does not propagate. Persist the defaulted finish via updateMessage so the next iteration's break check actually observes it.

packages/opencode/src/session/prompt.ts

@@ -1603,11 +1603,16 @@ NOTE: At any point in time through this workflow you should feel free to ask the
             // kilocode_change start - guard against providers that end the stream
             // without a terminal stop_reason (e.g. an Anthropic-style message_delta
             // with stop_reason: null followed immediately by message_stop). Without
-            // a finishReason, the loop-exit check below sees a falsy `finish` and
-            // keeps stepping forever. Default to "unknown" so the regular break
-            // condition fires when there are no tool calls, while still allowing
-            // the loop to continue when tool calls were emitted.
-            handle.message.finish = handle.message.finish ?? "unknown"
+            // a finishReason, the loop-exit check at the top of the next iteration
+            // sees a falsy `finish` (loaded from storage via filterCompactedEffect)
+            // and keeps stepping forever. Default to "unknown" and persist so the
+            // regular break condition fires when there are no tool calls — the
+            // tool-call path is unaffected because `!hasToolCalls` keeps the break
+            // gated when the assistant did emit tool calls.
+            if (!handle.message.finish) {
+              handle.message.finish = "unknown"
+              yield* sessions.updateMessage(handle.message)
+            }
             // kilocode_change end
 
             if (structured !== undefined) {