add /api/skills endpoint + capabilities page split (skills vs tools)
backend (main.py): /api/skills walks settings.skills_dir, parses
SKILL.md frontmatter (name, description), lists sibling .md files as
resources. cached for process lifetime, parallel to /api/abilities.
frontend (capabilities page):
- status strip: SKILLS · TOOLS · OPERATOR-GATED counts
- two visually-distinct sections: skills (load on demand, amber accent)
on top, tools (always available, default text) below
- detail pane branches by kind — skill view shows resource list;
tool view shows the operator-only flag
- keyboard nav skips section headers
- loq bump for the larger capabilities page