AI Skills

[NiklasRentzCAU]

Adds AI skills for more effective SPViz agent workflows.

This covers most common workflows with SPViz:

• orienting the user in SPViz
• modeling SPViz A2Ms and VC2Ms
• building SPViz and SPViz-generated tools
• implementing a project model generator
• a skill with packaged CLI tools (SPViz and KLighD)
• modeling difference visualizations
• modeling a project model via the project model DSL
• viewing project models together with KLighD
• visualization style customization in the generated code
• generic troubleshooting

This PR also adds release packaging for these skills and building source code artifacts into some skills:

• the SPViz CLI inside the cli-tools skill and .xtext files in troubleshooting and DSL modeling skills for better agent orientation.
• a Maven build profile downloading the KLighD CLI to the same skill as well, executed during release publishing
• the Appendix C chapter of my dissertation as plain .txt format for the style customitation skill

For quicker workflow turnarounds, a --validate command is added to both the SPViz CLI and the language server jar of generated visualization projects, making the language server now a combined language server and generic CLI for generated visualizations.

Adds a small fix for the generated diffdsl language registration.