Allow end-aligned truncation for path and branch footer items

Describe the feature or problem you'd like to solve

When the path or branch name is too long, only the end is truncated.

Proposed solution

Add a per-item truncation setting to  /footer  (and  /statusline ) for values such as the current working directory and Git branch. Support at least  start  (current behavior),  end , and optionally  middle  truncation. With  end  selected, render an ellipsis followed by the trailing portion of the value—for example,  …\foo\.worktrees\bar  and  …/feature-name —so the most distinguishing directory and branch suffix remain visible in narrow terminals. Persist the preference with the existing footer configuration.

Example prompts or workflows

No response

Additional context

No response

先定位 footer 和 statusline 的設定與渲染入口，然後追蹤目前路徑與分支值的截斷及持久化方式。驗證現有的從開頭截斷行為，並確定每個項目的開頭、結尾或中間偏好應放在哪裡。完成的標準是兩個介面都能保留該設定，並在窄終端中顯示要求的路徑或分支末尾部分，同時使用省略號。