feat: 提示词新增全局变量 DataDir + 触发合并/种子意图默认值调整

- prompt: 新增全局运行时变量 {{.DataDir}}(服务端数据根目录 s.m.dir),
  与 {{.Now}} 一样对所有 agent(planner/worker/mainagent/goals/chat 及自定义)可用;
  各 Vars 结构体加 DataDir 字段并在渲染时填入根 workDir,globalPromptVars 登记以便
  校验/UI 变量列表/预览识别(纯运行时变量,不入库,无需迁移)。
- trigger_merge_mode 默认 by_task→all(schema/config/后端兜底/前端初值同步)。
- seed_first_intent 默认 true→false(走标准先规划再执行);spawn_task 不再暴露该参数,
  工具建任务一律 false。

db/config.go

@@ -142,7 +142,7 @@ type Agent struct {
 	TriggerMaxParallel int    `json:"trigger_max_parallel"`
 }
 
-const agentCols = `id,key,name,COALESCE(description,''),role,builtin,enabled,COALESCE(max_turns,0),COALESCE(run_seconds,600),COALESCE(web_search,false),COALESCE(interactive_shell,false),COALESCE(wrapup_prompt,''),COALESCE(wrapup_max_turns,0),COALESCE(task_timeout_wrapup_prompt,''),COALESCE(task_timeout_wrapup_max_turns,0),COALESCE(trigger_run_mode,'serial'),COALESCE(trigger_merge_mode,'by_task'),COALESCE(trigger_max_parallel,5),llm_profile_id`
+const agentCols = `id,key,name,COALESCE(description,''),role,builtin,enabled,COALESCE(max_turns,0),COALESCE(run_seconds,600),COALESCE(web_search,false),COALESCE(interactive_shell,false),COALESCE(wrapup_prompt,''),COALESCE(wrapup_max_turns,0),COALESCE(task_timeout_wrapup_prompt,''),COALESCE(task_timeout_wrapup_max_turns,0),COALESCE(trigger_run_mode,'serial'),COALESCE(trigger_merge_mode,'all'),COALESCE(trigger_max_parallel,5),llm_profile_id`
 
 func scanAgent(sc interface{ Scan(...any) error }) (*Agent, error) {
 	var a Agent

db/schema.sql

@@ -300,7 +300,7 @@ CREATE TABLE IF NOT EXISTS agents (
     task_timeout_wrapup_prompt    TEXT NOT NULL DEFAULT '',
     task_timeout_wrapup_max_turns INTEGER NOT NULL DEFAULT 0,
     trigger_run_mode     TEXT    NOT NULL DEFAULT 'serial'  CHECK (trigger_run_mode IN ('serial','parallel')),
-    trigger_merge_mode   TEXT    NOT NULL DEFAULT 'by_task' CHECK (trigger_merge_mode IN ('by_task','all','none')),
+    trigger_merge_mode   TEXT    NOT NULL DEFAULT 'all' CHECK (trigger_merge_mode IN ('by_task','all','none')),
     trigger_max_parallel INTEGER NOT NULL DEFAULT 5,
     created_at        TIMESTAMPTZ NOT NULL DEFAULT now(),
     updated_at        TIMESTAMPTZ NOT NULL DEFAULT now(),
@@ -308,7 +308,7 @@ CREATE TABLE IF NOT EXISTS agents (
 );
 -- 加列迁移(已发版,旧库升级补列;新库 CREATE 已含。迁移不带 CHECK:旧库存量安全 + 后端写入白名单兜底)。
 ALTER TABLE agents ADD COLUMN IF NOT EXISTS trigger_run_mode     TEXT    NOT NULL DEFAULT 'serial';
-ALTER TABLE agents ADD COLUMN IF NOT EXISTS trigger_merge_mode   TEXT    NOT NULL DEFAULT 'by_task';
+ALTER TABLE agents ADD COLUMN IF NOT EXISTS trigger_merge_mode   TEXT    NOT NULL DEFAULT 'all';
 ALTER TABLE agents ADD COLUMN IF NOT EXISTS trigger_max_parallel INTEGER NOT NULL DEFAULT 5;
 -- per-agent LLM 绑定(agent 级默认模型):列自初版即在上方 CREATE 中,此 ALTER 仅为极旧库兜底(幂等)。
 ALTER TABLE agents ADD COLUMN IF NOT EXISTS llm_profile_id BIGINT REFERENCES llm_profiles(id) ON DELETE SET NULL;