chore: 提取默认预设 event.title 字数要求从 6-18 改为 6-10 字

- prompting/prompt-profiles.js: FALLBACK_DEFAULT_TASK_BLOCKS extract role/rules
- prompting/default-task-profile-templates.js: extract default-role / default-rules 模板
- maintenance/extractor.js: buildDefaultExtractPrompt 规则说明
- graph/schema.js: event.title hint

graph/schema.js

@@ -27,7 +27,7 @@ export const DEFAULT_NODE_SCHEMA = [
     label: "事件",
     tableName: "event_table",
     columns: [
-      { name: "title", hint: "简短事件名（建议 6-18 字，用于图谱显示）", required: false },
+      { name: "title", hint: "简短事件名（建议 6-10 字，用于图谱显示）", required: false },
       { name: "summary", hint: "事件摘要，包含因果关系和结果", required: true },
       { name: "participants", hint: "参与角色名，逗号分隔", required: false },
       {