dsh-skills-management: Add Model and Manual invocation switches for DSH Skill

`dsh-skills-management` is a DSH workflow plugin maintained by JayC-L. It centralizes the display of the Skill directory and provides separate controls for model invocation and user-initiated `/name` manual invocation based on the file source. During invocation, it reads the latest source files in real-time without modifying `SKILL.md`, copying references, or scripts, storing only invocation states and file locations in the strategy. The README specifies installation via the plugin manager or by downloading a Release package, requiring DSH version >=0.2.1-rc.5 <0.3.0-0. The article also covers four hard constraints on the management scope, directory refresh timing, the `~/.dsh/skills-management/disabled.json` field, and the policy of removing strategy entries without deleting source files for missing items. Furthermore, it discusses security boundaries such as loopback endpoints and the absence of telemetry collection. It also reminds users that the project has 1 star and advises checking the source code and MIT license before installation.