feat(agent): 按任务/意图预建 agent 工作目录，worker 免手动建目录

- 新增 ensureRunDir(base,taskID,intentID)：os.MkdirAll 建
  <workDir>/<taskID>[/i<intentID>]，返回路径；cmdOutDir 助手
- worker：CWD/ToolOutputDir/提示词指到 <workDir>/<taskID>/i<意图id>/
  (引擎预建)，删 workerArtifactSubdir，新 workerArtifactSpec 文案
- planner/mainagent：补 WorkingDir=<workDir>/<taskID>/ + ToolOutputDir
  (此前根本没设 WorkingDir)；artifactSpec 文案改为「本任务工作目录」

Co-Authored-By: Claude Opus 4.8 <[email protected]>

agent/mainagent.go

@@ -4,12 +4,12 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/Autumn-27/artex/db"
 	"github.com/Autumn-27/norma/agentcore"
 	"github.com/Autumn-27/norma/llm"
 	"github.com/Autumn-27/norma/permission"
 	actool "github.com/Autumn-27/norma/tool"
 	"github.com/Autumn-27/norma/transcript"
-	"github.com/Autumn-27/artex/db"
 )
 
 // MainAgent is the thin human-interface orchestrator (docs §4.2 / §7). The human
@@ -74,7 +74,9 @@ func (m *MainAgent) Chat(ctx context.Context, taskID int64, as *db.AssetStore, t
 	base := append(tsx.MainAgentTools(), actool.DefaultTools()...)
 	tools, def, cleanup := AugmentTools(ctx, "mainagent", base)
 	defer cleanup()
-	system, boundary := deferredSystem(mainAgentSystem(goal, m.workDir), def)
+	// 本任务的工作目录 <workDir>/<taskID>，先建好。
+	mainDir := ensureRunDir(m.workDir, taskID, 0)
+	system, boundary := deferredSystem(mainAgentSystem(goal, mainDir), def)
 	opts := agentcore.Options{
 		Provider:        m.prov,
 		SystemPrompt:    system,
@@ -93,10 +95,12 @@ func (m *MainAgent) Chat(ctx context.Context, taskID int64, as *db.AssetStore, t
 		BraveSearchAPIKey:  m.webSearch.BraveKey,
 		TavilySearchAPIKey: m.webSearch.TavilyKey,
 		WebSearchProxy:     m.webSearch.Proxy,
-		BashEnv:           proxyEnv(m.proxyAddr, m.proxyCACert), // Bash 子命令默认走代理+信任 CA
-		MaxTurns:          m.maxTurns,                           // 0 = unlimited (configurable in agent management)
-		Compaction:        compactionConfig(m.window),           // long chats stay within the window
-		Todos:             actool.NewTodoStore(),                // 会话级临时待办（TodoWrite），纯规划用，退出即丢
+		BashEnv:            proxyEnv(m.proxyAddr, m.proxyCACert), // Bash 子命令默认走代理+信任 CA
+		WorkingDir:         mainDir,                              // 本任务工作目录 <workDir>/<taskID>
+		ToolOutputDir:      cmdOutDir(mainDir),
+		MaxTurns:           m.maxTurns,                 // 0 = unlimited (configurable in agent management)
+		Compaction:         compactionConfig(m.window), // long chats stay within the window
+		Todos:              actool.NewTodoStore(),      // 会话级临时待办（TodoWrite），纯规划用，退出即丢
 		// 命中预算(步数)→ SDK 跑收尾:向用户输出一句进展总结。Prompt 与收尾轮数可后台编辑(默认 5 轮)。
 		Settlement: wrapupSettlement("mainagent", nil),
 	}