gewuji/dsh-plugin-work-notes: Add a work notes panel to the left sidebar of DSH

This is a pure front-end plugin for DSH (DeepSeek Harness). It provides a working note canvas in the left sidebar where cards can be freely dragged, scaled, and snapped. Cards feature start and end dates, and dates can be rescheduled by dragging within the calendar and Gantt chart views. Data is stored locally in the browser's `localStorage` without making any network requests. Installation supports pasting the repository URL via the graphical interface, running the command `dsh plugin --profile web add`, or copying via local absolute paths. Compatible with DSH 0.1.x, MIT License. Maintainer: Gewuji.