v3.4.1 — dsh 0.2.1 兼容：persona 移除 cwd 变量引用

dsh 0.2.1 compatibility fix. dsh 0.2.1-rc.2 dropped the built-in cwd prompt variable — the loop now registers only provider and model, and the working directory arrives as required runtime context (Current working directory: …, interpolate: false). xdev v3.4.0's persona prefix still interpolated {{cwd}}, and dsh's variable interpolation is strict, so every xdev run on dsh 0.2.1+ died during prompt assembly, before the first model request — the GUI showed 本轮运行失败/处理失败 with unknown prompt variable "{{cwd}}" in section "deployment:persona-prefix"; registered variables: provider, model. v3.4.0's dsh adaptation was verified on 0.2.0-rc.2, where cwd was still a registered variable, so the break only appeared after upgrading.

Fixed

• xdev 模式在 dsh 0.2.1+ 上每轮都失败 — agent.cordis.yml 的 persona prefix 删掉了 {{cwd}} 引用（保留 {{model}}），并在该行上方注释里钉住原因与版本边界，避免后续升级又把变量写回来。信息不丢：工作目录仍由 dsh 的 working-directory 服务以「必填运行时上下文」注入到模型。验证：按 dsh 的 !!js YAML 方言解析 preset 后，全树 {{…}} 扫描只剩 {{model}}；仓库与 ~/.dsh/.agent-presets/xdev 的 agent.cordis.yml diff 为空；84 项守卫测试全部通过，gen-dsh.mjs --check 无 stale。