fix: Git Workflow 多 Session 并发隔离改造 - Closes #124

核心变更:
- _common.sh: setup_worktree 改为 session-unique detached worktree (origin/main)
- 所有 Agent 文档移除 git checkout main / git pull origin main
- Feature branch 统一从 origin/main 创建: git fetch origin && git checkout -b <branch> origin/main
- CLAUDE.md: 新增工作区隔离章节, primary worktree 定义为只读参考区
- 新增 start_generic.sh: Generic session worktree 隔离启动器

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/start_qe_agent.sh

@@ -19,15 +19,13 @@ source "$SCRIPT_DIR/_common.sh"
 setup_worktree "$GITEA_USER"
 
 # Cleanup worktree on exit (optional, comment out to keep for debugging)
-trap 'cleanup_worktree "$GITEA_USER"' EXIT
+trap 'cleanup_worktree' EXIT
 
 banner "QE"
 require_token
-
-AGENT_CONF="$_MAIN_REPO_DIR/.claude/agents/qe-agent.md"
 launch_agent \
     "qe-agent" \
-    "$AGENT_CONF" \
+    "$PROJECT_DIR/.claude/agents/qe-agent.md" \
     "QE-Agent" \
     "执行一次 Issue 巡检（单次任务，不要用 /loop）：
 1. python scripts/agent_poller.py --action list --labels test-code 检查 test-code Issue