fix: persist modelContextLimit immediately after caching

The chat.message save always ran before the system.prompt hook cached
modelContextLimit, so the value never reached disk and restarts could
not restore it. Save right after caching in the system.prompt hook.

Author: Neko-Yukari

lib/hooks.ts

@@ -68,6 +68,12 @@ export function createSystemPromptHandler(
         if (input.model?.limit?.context) {
             state.modelContextLimit = input.model.limit.context
             logger.debug("Cached model context limit", { limit: state.modelContextLimit })
+            // 立即持久化：opencode 的 chat.message 保存总在 system.prompt 缓存
+            // 之前运行，若不在此保存，modelContextLimit 永远无法写入磁盘，
+            // 重启后第一轮阈值无法按百分比解析。
+            if (state.sessionId) {
+                void saveSessionState(state, logger)
+            }
         }
 
         if (state.isSubAgent && !config.experimental.allowSubAgents) {