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_generic.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# Generic session 启动脚本 — 为人类用户提供 worktree 隔离
+# 用法: bash scripts/start_generic.sh
+# GITEA_USER 默认 pzhangzywl（人类用户），可通过环境变量覆盖
+
+set -eu
+
+export GITEA_USER="${GITEA_USER:-pzhangzywl}"
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+source "$SCRIPT_DIR/_common.sh"
+
+setup_worktree "$GITEA_USER"
+trap 'cleanup_worktree' EXIT
+
+banner "Generic"
+require_token
+
+echo "工作目录: $PROJECT_DIR"
+echo ""
+cd "$PROJECT_DIR"
+claude