aawef/dsh-skill-manager-tags

Tag-based skill filtering: attach tags to DSH skills, then hand each workspace or conversation only the subset its boolean tag expression selects (for example `pdf + docx` or `aegis * plugin`). Excluded skills are deny-shadowed out of the model catalog rather than merely hidden in the settings UI; skills outside the expression can still be added by hand or force-disabled, and the bundled `tagging-skills` teaches the agent to derive a tag set from the machine it is running on.